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 A
ABO TYPING
ABO typing is done to determine your blood type. Are you A, B, AB or O? It is done as part of a blood transfusion, organ donation, or paternity test. For people who simply want to know their own blood type, we suggest donating blood. They will tell you your blood type for free.
ACE
Angiotensin Converting Enzyme is used to help diagnose and treat Sarcoidosis (a lung condition). It can be abnormal in other lung diseases.
ACTH STIMULATION TEST
The ACTH Stimulation test is carried out to diagnose Addison’s disease (failure of the adrenal gland). It involves two blood collections and an injection of ACTH (Cortrosyn ™). For more information, please see the section on Adrenal Disease.
ALBUMIN
Albumin is a protein comprising half of all the protein in the serum. Albumin regulates the pressure in tissues (oncotic pressure), serves as a nutritional source, and carries toxins and metabolites in the blood stream. It is low in severe nutritional deficiency, chronic liver disease, and nephrotic syndrome.
ALCOHOL
Ethanol can be detected and quantified in body fluids. Ethanol is removed from the body at 150 mg/Kg body weight per hour, or 1 beer per hour or 1 ounce of whiskey per hour. The correlation between blood concentrations and symptoms are:
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mg/dL
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mmol/L
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50 – 100
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11 – 22
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Incoordination, sensory impairment, impaired driving
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80
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17
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Legal intoxication
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100 –150
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22 – 33
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Personality and mood changes, slurred speech
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150 – 200
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33 – 43
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Poor coordination, slow reaction time, impaired thought processes
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200 –300
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43 – 65
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Ataxia, visual disturbances, nausea and vomiting
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300 – 400
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65 – 87
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Stupor, hypothermia
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500 – 700
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108 – 130
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Unconsciousness, respiratory failure, death
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ALDOSTERONE
Aldosterone is a substance manufactured by the adrenal glands that controls salt balance. A tumor in the adrenal gland can produce aldosterone in excess and this will cause high blood pressure.For more information, please see the section on Adrenal Disease.
ALKALINE PHOSPHATASE
Alkaline Phosphatase (AP) is an enzyme produced by the liver and bone. AP is increased in a variety of bone disorders. It is also increased in obstructive (cholestatic) liver disease.
ALPHA - 1 ANTITRYPSIN
Alpha-1 Antitrypsin is an enzyme that removes trypsin and prevents it from damaging the tissues that produce it. A genetic defect (A1AT deficiency) causes liver disease and lung disease.
ALT
Alanine Aminotransferase (ALT) is a liver enzyme that is increased in inflammation of the liver. Minor increases are seen with “flu” and major increases (500-3000) are seen in hepatitis.
AMMONIA
Protein digestion leads to an increase in ammonia in the blood stream. Ammonia is toxic and affects the brain. High levels of ammonia may occur in advanced liver disease since the liver usually breaks down ammonia. This is not a very reliable test and must be interpreted with good knowledge of the patient’s condition.
AMYLASE
Amylase is a digestive enzyme produced by the pancreas. In a disorder known as pancreatitis, the pancreas develops inflammation and severe abdominal pain is caused. The serum and urine Amylase values increase significantly.
ANDROSTENEDIONE
Androstenedione is an androgen (male hormone) produced by the adrenal gland (and to some degree by the ovary).
ANTIBIOTIC SUSCEPTIBILITY TEST
If a bacteria is found when a swab is cultured, a sample of the bacteria can be grown on a separate culture plate. Small discs (like confetti) that have been soaked with various antibiotics are also placed on the culture plate. The lab can then tell which antibiotics are most effective against the bacteria.
ANTICARDIOLIPIN ANTIBODY
Anticardiolipin antibody is developed by some people and it interferes with the normal blood clotting sequence in such a way that the blood clots too much. This can cause strokes, blocked blood vessels, and intrauterine fetal death.
ANTI-DNA
Anti-DNA is an autoantibody (antibody produced against your own tissue). A positive test is strong evidence for Lupus Erythematosis. A negative test does not rule out this diagnosis.For more information, please see the section on Lupus.
APOLIPOPROTEIN A-1
Apolipoprotein A-1 is the protein that makes up the HDL-Cholesterol. Like the HDL, low values are one of the most reliable predictors of Coronary Atherosclerotic Disease (CAD).For more information, please see the section on Cholesterol.
APOLIPOPROTEIN B – 100
Apolipoprotein B is the major protein that makes up all of the lipoproteins other than HDL. Apolipoprotein B-100 is the major constituent of LDL-Cholesterol. Increased levels are associated with a higher risk of Coronary Atherosclerotic Disease (CAD). For more information, please see the section on Cholesterol.
AST
AST (Aspartate Aminotransferase) is a liver enzyme that is increased in inflammation of the liver. Minor increases are seen with “flu” and major increases (500-3000) are seen in hepatitis.
B
BETA 2 MICROGLOBULIN
b2-microglobulin is a low molecular weight protein related to the immunoglobulins. It is increased in various malignant and immune disorders where it is produced proportionally to the tumour load, disease activity and prognosis. It is also increased in chronic inflammation, liver disease, acute viral disease, renal failure, and chronic cadmium exposure (a good industrial marker) – urine values increase. Beta 2-Microglobulin can be used in assessing renal function, particularly in kidney-transplant recipients and in patients suspected of having renal tubular disease. It also can serve as a nonspecific but relatively sensitive marker of various neoplastic, inflammatory, and infectious conditions. Early hopes that it would be a useful serum test for malignancy have not been fulfilled, but it does have prognostic value for patients with lymphoproliferative disease, particularly multiple myeloma. More recent reports have suggested a role for Beta 2M as a prognostic marker in human immunodeficiency virus (HIV) infection.
BICARBONATE
Bicarbonate is the main acid buffer in the blood stream. Low values occur in metabolic acidosis and respiratory alkalosis. High values occur in metabolic alkalosis and respiratory acidosis.
BILIRUBIN (DIRECT)
Bilirubin is the end result of hemoglobin breakdown and is removed from the body by the liver. Increased bilirubin comes from liver disease or from increased hemoglobin breakdown. The direct bilirubin has been conjugated in the liver. Thus, an increase in this fraction indicates an obstructive liver disorder. See Bilirubin (Total) below.
BILIRUBIN (TOTAL)
Bilirubin is the end result of hemoglobin breakdown and is removed from the body by the liver. Increased bilirubin comes from liver disease or from increased hemoglobin breakdown. Bilirubin is increased in the serum in the following disorders:
·In hemolysis, the excessive breakdown of red cells causes the bilirubin to increase.
·In obstructive liver disease (bile duct obstruction or cholestasis) the bilirubin is conjugated in the liver but not removed. Thus the conjugated or “direct” bilirubin is raised.
·In hepatocelluar disease the bilirubin may rise.
BLEEDING TIME
To assess the ability of the body to control bleeding, a test is performed by cutting the skin and timing how long it takes to stop bleeding. This is now an obsolete test.
BLOOD CULTURE
To determine if bacteria are growing in someone’s blood stream, a sample of blood is removed and placed in a bottle of nutrients. It can then be examined at intervals to see if bacteria have grown.
BLOOD LEAD
Lead poisoning is generally due to chronic overexposure in industry or in children with pica (compulsive eating of non-foods). The overt syndrome involves GI symptoms, convulsions, coma, abdominal pain, neuropathy, anemia, and nephropathy. Chronic exposure may cause decreased mental functioning without ever causing the overt syndrome. The Canadian Intervention Level is 1.21 mmol/L (26 mg/L). The new CDC (USA) standard proposes 0.48 mmol/L (10 mg/L). A paper by Drs. Shaun Peck and Gillian Lockitch states that 7% of pre-school children in Vancouver have blood lead > 0.48 mmol/L.
BLOOD PORPHYRINS
A group of inherited disorders of hemoglobin metabolism are called porphyrias. They result in a spectrum of syndromes from mental derangement, light sensitive skin disease, and acute abdominal pain. These disorders can be diagnosed by measuring porphyrins in the blood, serum, urine, and feces.
C
C - REACTIVE PROTEIN
C-Reactive Protein (CRP) is a protein that increases in response to inflammation. Recent evidence has suggested it may be useful in predicting heart attacks.
C DIFFICILE
Sometimes when antibiotics are taken orally they disrupt the normal bacteria in the bowel and allow bacteria known as Clostridium difficile to grow. C. difficile produces a toxin that can cause diarrhea.
CA 125
CA 125 is a tumour marker of ovarian cancer. The CA-125 molecule is widely distributed on the surface of both healthy and malignant cells of mesothelial origin including pleural, pericardial, peritoneal and endometrial cells, as well as in the normal genital tract and amnionic membrane. It is not a diagnostic test for ovarian cancer. It is used to monitor ovarian cancer after treatment. Ca-125 is increased in 82% of patients with ovarian cancer. Values > 35 U/L are predictive of intra peritoneal or recurrence. The CA 125 is increased in 80% epithelial ovarian cancer, 90% nonmucinous ovarian cancer, some advanced endometrial cancer, 60% pancreatic cancer. It is also increased in ovarian teratoma. Only 1% of normal healthy patients have an elevated CA-125. Benign conditions associated with CA-125 increase includes: menstruation, pregnancy, benign pelvic tumors, pelvic inflammatory diseases, ovarian hyperstimulation syndrome, endometriosis, peritonitis and many diseases leading to pleural effusion or ascites. Ca-125 values of up to 5000 unit/mL have been reported in some benign conditions.
CA 15-3
CA 15-3 is a protein (also known as Breast Cancer Mucin) that is produced by many cancers of the breast. It is not used for screening. It is recommended as a follow-up after breast cancer has been treated. In some cases this will allow a relapse to be detected before becoming clinically apparent.
CALCIUM
Serum calcium is held within tight limits in the serum by a complex sequence of hormones. Increases in serum calcium are seen with: parathyroid adenoma, pheochromocytoma, lymphoma, parathyroid carcinoma, tertiary hyperparathyroidism (chronic renal failure), PTH secreting tumours, metastatic carcinoma to bone (breast, lung, kidney, lymphoma, leukemia), vitamin D overdosage, multiple myeloma, tumour producing a hormone that acts like PTH but does not cross react in the assay (parathyroid hormone related peptide (PTHRP)), Sarcoidosis, vitamin D intoxication, milk alkali syndrome, Paget’s disease, thyrotoxicosis, acromegaly, and acute tubular necrosis.
The reasons for having a low calcium are: hypoalbuminemia (low albumin), decreased PTH (surgery to the neck, involutional or autoimmune), PTH insensitivity (pseudohypoparathyroidism), vitamin D deficiency (dietary, malabsorption), nutritional, malabsorption, chronic renal failure, magnesium deficiency, anticonvulsant therapy, acute pancreatitis, massive blood transfusion, osteomalacia, proximal and distal renal disease, alcoholism, cirrhosis, diuretic, hyperphosphatemia (acute and chronic renal insufficiency, phosphate infusions), post parathyroidectomy, hyperadrenalism, neonatal tetany, acute pancreatitis, magnesium deficiency, and renal tubular acidosis.
CALCULUS
Calculus means “stone”. Stones that form in the urinary system (kidney, ureter, bladder) can be analyzed in the lab to determine what they are made from. This may help determine the cause of the stone formation.
CARBAMAZEPINE
Carbamazepine (Tegretol) is a drug used to treat seizures. An active metabolite increases in renal disease. Decreased values are seen with Phenobarbital (increases metabolism) and Phenytoin (increases metabolism). Measurement is carried out to adjust the dosage. For more information, please see the section on Therapeutic Drug Monitoring.
CAROTENE
Carotene is found in vegetables and because it is not soluble in water it must be absorbed from the intestine into the blood stream along with fat. The measurement of carotene in serum is therefore a rough gauge of the efficiency of fat absorption.
CATECHOLAMINES
Catecholamines is name for metabolites of adrenaline produced in the adrenal medulla. Catecholamines are increased in the urine in stress and in a rare tumor that causes hypertension and episodes of sweating called Pheochromocytoma. For more information, please see the section on Adrenal Disease.
CERULOPLASMIN
A copper containing protein, ceruloplasmin is markedly decreased in Wilson’s disease, a condition in which copper deposits in the liver, brain, and eye.
CHLAMYDIA
Chlamydia is a microorganism species that causes a variety of diseases. Most often it is studied in genital cultures or urine, as it is a common sexually transmitted disease (STD).
CHLORIDE
One of the electrolytes in the serum, chloride is the negatively charged ion that allows the positively charged sodium and potassium to exist in the blood stream.
CHOLESTEROL
Cholesterol is a blood lipid that is correlated with heart and artery disease. In BC, Cholesterol testing is governed by a Protocol developed by the Medical Plan and the BCMA.
BC MSP/BCMA 1996 Cholesterol Testing Protocol For adults Under 69 Years
Recommendations
1. Who should be tested?
Asymptomatic men and women aged <69 who have one or more of the following risk factors for coronary artery disease (CAD):
- age: men >45 years, women >55 years
- smoking
- hypertension (>140/90 mm Hg. or on anti-hypertensive medication)
- diabetes mellitus
- abdominal obesity
- family history of premature CAD (angina pectoris, myocardial infarction, angiographic evidence of CAD, history of coronary artery bypass grafting or angioplasty, or sudden death in a first degree* male relative at age <55 years or first degree* female relative at age <65 years) or family history unknown
- Comment: Note that CAD is much less common in pre-menopausal women than in men of the same age and that drug treatment in these women is needed only rarely unless they have familial hypercholesterolemia.
- Men and women aged <69 years who have documented CAD (angina pectoris, myocardial infarction, angiographic evidence of CAD, or history of coronary artery bypass grafting or angioplasty).
- Men and women who have physical signs compatible with familial hyper-cholesterolemia (eg. tendinous xanthomata, premature arcus senilis) or who have first degree relatives with these physical signs or with documented severe hyper-cholesterolemia.
2. What tests to do?
Measure total cholesterol, high density lipoprotein (HDL) cholesterol, and triglycerides (to calculate low density lipoprotein cholesterol) once (but not within 3 months after myocardial infarction or within 1 month after another acute illness such as infection).
3. Who should not be tested?
- Asymptomatic men aged <45 and women aged <55 who have no risk factors for CAD.
Interpretation:
Cholesterol in the serum is present in several different forms. The cholesterol molecule is the same in each. However, the cholesterol molecule is covalently bound in a complex arrangement with specific proteins known as apolipoproteins to form lipoproteins that can be distinguished on the basis of their relative molecular weight. These molecular arrangements make the cholesterol soluble and help direct the cholesterol to a specific destination in the body.
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HDL Cholesterol
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LDL Cholesterol
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Low density lipoprotein cholesterol
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“Bad” cholesterol. High values are an indepenent risk factor.
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VLDL Cholesterol
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Very low density lipoprotein cholesterol
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This cholesterol has no influence one way or another on atheroscleosis. It is bound up with triglyceride in its lipoprotein and is depepndent on how much trig is present.
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Total Cholesterol
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The total of HDL, LDL, and VLDL.
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Triglycerides
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Three long chain fatty acids linked together by a glycerol molecule.
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Relates to carbohydrate and liver metabolism.
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CHOLESTEROL, HDL
HDL is the High Density Lipoprotein Cholesterol. This is the “good” cholesterol that is being removed from the arteries. See “Cholesterol” above.
CHOLINESTERASE
There are two types of cholinesterase test. One to detect exposure to organophosphorus insecticides. The other is used to determine whether a patient can break down the muscle paralyzing drugs that are used in anesthetics.
CITRATE, URINE
A substance that prevents the formation of urinary stones. People with low values are susceptible to stone formation.
CK MB
Creatine Kinase (CK) is a muscle enzyme. The CK-MB is the form that is found in heart muscle. CK-MB is present after the heart muscle has been damaged and is therefore used as a “marker” of heart attacks.
COLD AGGLUTININS
A number of diseases result in the production of IgM antibodies (occasionally IgG) that coat red blood cells. They are so called because their optimal action in causing red cell damage at temperatures lower than 37°C. The test is used in the diagnosis of Hemolytic anemia. Cold agglutinins are found in a number of disorders: Idiopathic (unknown causes) 25%, drug induced (15%), neoplasia 15% (lymphoma, leukemia, carcinoma), infections 10% (mycoplasma, viral pneumonia, infectious mononucleosis), collagen diseases 2% (SLE, Rheumatoid arthritis), and other 5%. cold hemaglutinin disease (IgM mediated) usually occurs in persons over 50 yoa (women more common than men). Patients may present with acrocyanosis, Raynaud’s, or even hemolysis following exposure to the cold.
COMPLEMENT C3
The complement system consists of an interacting group of circulating proteins that mediate the inflammatory response and help to destroy foriegn particlate matter (particularly microorganisms and viruses). The complement proteins circulate as inactive precursors that become activated in a precise sequence that allows mediation of their collective response.
C3 is one of the “routine” complement tests. Patients with homozygous C3 deficiency have an increased incidence of bacterial infections. A decrease in C3 is associated with complement fixing disorders: acute glomerulnephritis, membranoproliferative glomeruloneohritis, immune complex disease, and active SLE.
COMPLEMENT C4
The complement system consists of an interacting group of circulating proteins that mediate the inflammatory response and help to destroy foriegn particlate matter (particularly microorganisms and viruses). The complement proteins circulate as inactive precursors that become activated in a precise sequence that allows mediation of their collective response.
C4 is part of the classical pathway of complement. C4 measurements are used with C3 to determine which pathways have been activated. Value is low in: SLE, early glomerulonephritis, immune complex disease, cryoglobulinemia, and Hereditary Angioneurotic Edema.
COPPER (SERUM)
Copper in serum is measured to confirm a diagnosis of Wilson’s Disease (see discussion on ceruloplasmin).
CORTISOL
Cortisol is the main product of the adrenal gland. Excess cortisol production is called Cushing’s Syndrome. Inadequate cortisol production is called Addison’s syndrome. Increased values are seen in adrenal tumour, pituitary tumour, stress, depression, hypoglycemia, and some drugs (hydrocortisone, methylprednisolone). Decreased values are seen in adrenal failure, pituitary insufficiency, and some drugs (prednisone, dexamethasone). For more information, please see the section on Adrenal Disease.
CPK
CPK or CK stands for Creatine Phosphokinase or Creatine Kinase. It is a muscle enzyme that is increased in muscle disease.
Specifically, increases are seen in: myocardial necrosis (heart attack), muscle trauma, strenuous physical exercise, surgery, burns, alcoholic myopathy, alcoholic withdrawal syndrome, myopathy, hypookalemia, hypothyroidism, renal failure, renal cell carcinoma, seminoma, carcinoma of the lung, CLL, obstructive lung disease, pneumonia, febrile infections, and macro-CK (an immune complex).
CREATININE
Creatinine is a waste product of muscle metabolism. It is produced by the body in rough proportion to the amount of muscle you have. It is then removed by the kidney. Increases in serum creatinine are due to increased production (rapid muscle breakdown, fever, burns, trauma) or decreased removal (kidney failure).
CRYOFIBRINOGEN
A peculiar form of fibrinogen (a clotting protein) that coagulates when the blood drops below 37 degrees C.
CRYOGLOBULIN
Cryoglobulins are protein complexes which precipitate at temperatures below normal body temperature (usually 4° C). Patients may suffer from cold induced precipitation of protein in small, peripheral blood vessels causing vascular purpura, bleeding, urticaria, Raynaud’s, pain and cyanosis. Some patients have Essential Mixed Cryoglobinemia that presents with purpura, arthralgia, weakness, lymphadenopathy, hepatosplenomegaly, and adrenal failure.
CULTURE FOR DERMATOPHYTE
Scrapings from skin lesions are grown on gelatin media to identify any skin fungi that may be present.
CYCLOSPORINE
Sandimmune Ò (Cyclosporine) is a drug used in organ transplant patients that reduces the “rejection” of the transplant. It acts by interfering with interleukin-2 (a growth factor for T-lymphocytes). It is measured to keep the cyclosporine level between critical levels. (Enough to do the job but not enough to cause toxicity.) For more information, please see the section on Therapeutic Drug Monitoring.
D
DEOXYPYRIDINOLINE CROSSLINK
Deoxypyridinoline crosslinks are the waste products of bone matrix resorption. The amount found in the urine is directly related to the rate at which bone is being resorbed. For more information, please see the section on Osteoporosis.
DHEA
DHEAS is Dehydroepiandrosterone and it is the main androgen of the adrenal gland. Its measurement is a good indicator of whether the adrenal gland is producing too much androgen. DHEA has gained popularity as a substance that may increase muscle strength and the general level of energy and vigor. There is not much experience measuring DHEA to determine whether this substance should be taken or what effect it has had after being taken.
DHEAS
DHEAS is Dehydroepiandrosterone sulphate and it is a metabolite of DHEA, the main androgen of the adrenal gland. Its measurement is a good indicator of whether the adrenal gland is producing too much androgen.
DIGOXIN
A heart drug that helps the contraction of the heart muscle. There is very little difference between the blood concentration where therapy is optimal and where toxicity can occur. For more information, please see the section on Therapeutic Drug Monitoring.
DRUG SCREEN
A group of tests carried out to detect the presence of drugs of abuse (cocaine, heroin, morphine, amphetamines, cannabis, etc.).
D-XYLOSE FASTING
A test of how well the intestine can absorb nutrients. A drink of xylose sugar is given and urine is collected for five hours. The amount of xylose in the urine indicates how efficient the absorption is.
E
ELECTROPHORESIS
A technique whereby the various proteins in a body fluid can be separated using an electric field. They can then be examined for abnormalities.
ENA
In certain autoimmune diseases the body forms antibodies to proteins which are found in the nucleus. The ENA test consists of an examination for four autoantibodies: Sm, RNP, SSA, SSB (and sometimes Scl 70). The interpretation of this panel is outlined below:
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Sm
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A confirmatory test for SLE if the patient has an increased ANA and aDNA. Often heralds CNS or renal complications).
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RNP
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Positive in 35 – 40 % of persons with SLE. Also + in Mixed Connective Tissue Disease (if RNP is the only antibody positive then renal complications are less likely).
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SSA (Ro)
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Positive in 25% of SLE patients. Positive in 40% of Sjogren’s Syndrome. Also positive in Antibody negative SLE, in infants with congenital complete heart block, and in neonatal lupus.
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SSB (La)
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Positive in 10 – 15% of SLE and 10 – 15% Sjogren’s disease, also positive in antibody negative SLE and Subacute SLE.
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For more information, please see the section on Lupus.
ESR (WESTERGREN)
Blood is placed in a long tube that is held vertically for one hour. The red cells will fall (or sediment). The height of the sedimented cells correlates with non-specific inflammation.
ESTRADIOL
17b-Estradiol is the dominant form of estrogen in the human body. It is normally produced by the ovary, the adrenal gland (small), and by peripheral conversion of adrenal androgens. It is measured to determine excessive estrogen in men and children. It is not as useful in determining reduced estrogen in women because the female reference range is very wide and reductions may remain in the normal range. Increased values are seen in children with: precocious puberty, estrogen producing tumours, and ingestion of exogenous estrogen. Male adults have increased values in estrogen producing tumours, gynecomastia, cirrhosis of the liver (metabolic breakdown imbalance), feminizing testes syndrome, estrogen medications, and spironolactone medication. Elevated values in female adults are difficult to distinguish from normal, and are found with Estradiol containing medications and pregnancy.
Decreased values are not generally detectable in children and male adults. In women, low values accompany ovarian failure, menopause, pituitary failure, and Turner’s syndrome.
F
FECAL FAT
Fat can be found in feces using a special stain and a microscope. Increased fat in feces indicates fat malabsorption. A new test, the Malitest, uses the breath measurement of a non-radioactive isotope of carbon (C-13) after eating a fatty mixture.
FECAL MEAT FIBERS
Fecal meat fibers indicate incomplete digestion and absorption.
FERRITIN
Ferritin is a test that indicates how much iron you have in your iron stores. Values less than 10 indicate iron deficiency and less than 20 indicate impending iron deficiency. High values are seen in excess iron syndromes (hemochromatosis) and in inflammation of iron storage tissues (e.g. hepatitis). For more information, please see the section on Hemachromatosis.
FIBRINOGEN
Fibrinogen is an important protein in the blood clotting mechanism. It is measure to determine the nature of bleeding disorders.
FLUORIDE
Fluoride is not a natural human element. It is added to drinking water to strengthen teeth. It has been used as a treatment for osteoporosis. It is measured occasionally to monitor this therapy or to diagnose toxic exposure.
FOLATE
Folate (Folic acid and folinic acid) is a vitamin. Low levels are exceedingly rare these days because folate is such a common food additive. Low folate is due to extreme dietary deficiency and causes a particular form of anemia and skin disease. High levels are only seen with folate ingestion. High homocystine may be due to relative folate deficiency. Folate deficiency has been implicated as a cause of neural tube defects in unborn babies.
FSH
Follicle Stimulating Hormone (FSH or follitropin) is a pituitary hormone that controls the maturation of “eggs” in the ovary and spermatozoa in the testes. It goes up in ovulation and in ovarian or testicular failure (including menopause). It is low in infertility and pituitary insufficiency. Its level varies throughout a normal menstrual cycle.
G
GGT
Gamma Glutamyl Transpeptidase is an enzyme found in the liver. It goes up in liver disease and when the liver is challenged to detoxify a substance such as alcohol or certain drugs.
GLUCOSE
Glucose is sugar. Its level is under the control of insulin. It is increased following meals and in diabetes. It may be low in response to meals (reactive hypoglycemia) or in excess insulin situations (too much insulin administration without food or an insulin-secreting tumor). Its main use is the diagnosis of diabetes or monitoring diabetic therapy. For more information, please see the section on Diabetes.
GLUCOSE GESTATIONAL
Pregnant women are usually checked for the presence of Gestational Diabetes.
Screening for Gestational Diabetes
A 50 gram glucose drink is administered between the 24th and 28th week without regard to time of day or time of last meal. The serum glucose is measured 1 hour later. A value of glucose equal to or greater than 7.8 mmol/L (140 mg/dL) indicates the need for a full diagnostic glucose tolerance test.
Full diagnostic Tolerance Test
A 100 gram oral glucose load is administered in the morning after an overnight fast of more than 8 hours but less than 14 hours, and after at least 3 days of unrestricted diet (150 grams of carbohydrate (650 cal) ) and normal physical activity.
Venous glucose is measured at Fasting, 1, 2, and 3 hours post drink. Subjects should remain seated and should not smoke during the test. Values greater than specific limits are judged to be abnormal. For more information, please see the section on Diabetes.
GLUCOSE TOLERANCE
The Glucose Tolerance test is the definitive test for diabetes mellitus. It is only carried out when this diagnosis cannot be made from single glucose measurements. It consists of taking a sugar drink followed by several blood glucose measurements. For more information, please see the section on Diabetes.
GRAM STAIN
The gram stain is the microscopic examination of a slide from a microbiology swab or a microbiology plate. A special stain is used. This study shows the presence of bacteria if they are present and categorizes them as gram positive (stain accepting) or gram negative. The test allows for a rapid initial assessment of bacterial infection.
H
HAPTOGLOBIN
Haptoglobin is a protein that “mops up” hemoglobin that is free (outside the red cells) in the serum. After binding hemoglobin it is removed from the serum. Low levels are found in red cell destruction (hemolytic anemia). The test has marginal value.
HCG
Human Chorionic Gonadotropin (hCG) is a hormone produced by a pregnancy (chorion layer of the placenta) as a way to nurture the pregnancy in the first few months. It is present in the maternal blood on the first day the pregnancy is established. It moves quickly from the blood into the urine. The detection of hCG is the basis of pregnancy tests. Quantitative measurements of hCG are used to diagnose pregnancy and reveal problems such as ectopic pregnancy or hydatidiform mole, spontaneous abortion, or tumors such as choriocarcinoma of the ovary or testes. HCG is also part of the Triple Marker Test. For more information, please see the section on Tests in Pregnancy.
HEMATOLOGY PANEL
The Hematology Panel (profile) is the mainstay of hematology diagnosis. It consists of an analysis in a large automated analyzer. For more information on the Hematology Profile click here.
HEMOGLOBIN
Hemoglobin is a complex protein containing iron that is responsible for carrying oxygen from the lungs to all the tissues of the body. It is measured as part of the hematology panel. Low hemoglobin is anemia. High hemoglobin is polycythemia.
For more information, please see the sections on the Hematology Profile and Anemia.
HEMOGLOBIN A2
Hemoglobin A2 is one of the forms of Hemoglobin. It is measured as part of an investigation to determine whether you have an abnormal type of hemoglobin (hemoglobinopathy) or an abnormal production system for hemoglobin (thalassemia). For more information, please see the section on Thalassemia.
HEMOGLOBIN, FETAL
Hemoglobin F is normally found in unborn babies and newborns. It is also present in adults with abnormal hemoglobin production.
HEPATITIS A IGM
Hepatitis A IGM is the standard test for the presence of Hepatitis A infection. A positive test indicates that Hepatitis A infection has occurred in the past six months. A negative test indicates no infection from this agent in the past six months. For more information, please see the section on Hepatitis.
HEPATITIS B CORE ANTIBODY
A positive HBcAB test indicates the presence of antibodies to the Hepatitis B virus. It is present very early on in a Hepatitis B infection and may stay positive for decades after the infection has resolved. Thus, a positive does not diagnose Hepatitis B; the Hepatitis B antigen test must be done to diagnose the presence of infection. For more information, please see the section on Hepatitis.
HEPATITIS B SURFACE AG
HBsAG is the test that tells whether the Hepatitis B virus is present. A positive test is found in active Hepatitis B infection, in chronic Hepatitis B, and in the Hepatitis B carrier state. For more information, please see the section on Hepatitis.
HEPATITIS BE ANTIGEN
HBeAG is positive when a Hepatitis B infection is very highly contagious. For more information, please see the section on Hepatitis.
HGB ELECTROPHORESIS
Hemoglobin electrophoresis was the main test to detect the presence of abnormal hemoglobin formation. Today, we do this study using High Pressure Liquid Chromatography but the name “electrophoresis” is still commonly used. For more information, please see the section on Thalassemia.
HGB A1C
Normal hemoglobin picks up glucose molecules that bind to it (glycosylation). The binding increases with generally elevated glucose over a period of time. Because the life span of a red cell is about 120 days the amount of glycated hemoglobin is a measure of the “average” blood glucose level over a four-month period. Its measurement is therefore recommended in all diabetics every 3-4 months as a way of assessing how good your diabetic control is. For more information, please see the section on Diabetes.
HGH
Human Growth Hormone is produced by the pituitary gland. It stimulates the growth of bones. Too much causes giantism and acromegaly. Too little results in dwarfism.
I
IGA
IgA is a type of antibody that is found on mucous membranes, (e.g. gastrointestinal tract, vagina). If deficient, patients may suffer from chronic diarrhea and certain types of recurrent infections.
IGE
IgE is a type of antibody that mediates the allergic reaction. It is normally very useful in removing unwanted materials from the body. In allergic persons the level may be abnormally high. Thus, it can be used to tell if a condition is allergic in nature. It does not reveal to what a person may be allergic. For this purpose, the Specific Allergen IgE test is used. For more information, please see the section on Allergies.
IGG
IgG molecules are the main type of antibodies that circulate in the blood stream. General increases in IgG accompany infections and inflammation and malignancy of the antibody producing cells. Decreases occur in some infections and may also be due to a genetic or acquired defect. When the IgG is low a person may be susceptible to infections. For more information, please see the section on Multiple Myeloma.
IGM
IgM molecules are antibodies that are recently formed and appear early in infections. Increased values are seen in: acute stimulation of the immune system (immunization, viral infections), selective increase is seen in neoplasia, IgM myeloma, and Waldenstrom’s macroglobulinemia. Decreased values are seen in: children, agammaglobulinemia (inherited) and myeloma. For more information, please see the section on Multiple Myeloma.
IMMUNOFIXATION URINE
Urine Immunofixation is a chemical method for identifying abnormal proteins in the urine. It is used in the diagnosis and monitoring of multiple myeloma. For more information, please see the section on Multiple Myeloma.
INR
International Normalized Ratio (also known as the Prothrombin Time) is a test that measures defects in part of the clotting mechanism. It is used to detect clotting abnormalities. However, it is mainly used to measure the effect of “blood thinning” medications such as Warfarin or Coumadin. For more information, please see the section on Anticoagulant Monitoring.
IRON
Iron is an essential nutrient required for normal hemoglobin formation. Inadequate iron may lead to anemia. The test is used to measure iron stores although the Ferritin test is better in most circumstances
J
JOINT FLUID CRYSTAL
The diagnosis of the cause of a swollen joint may be enhanced by removing some of the joint fluid and examining it under a microscope. Gout is characterized by the presence of uric acid crystals.
JOINT FLUID DIFFERENTIAL
The cells in a joint fluid are examined to determine the cause of a joint sweling.
JOINT FLUID, PROTEIN
The amount of protein in a joint fluid helps to determine the cause of the swelling.
K
KOH
The KOH test is used to identify fungus infections of the skin.
L
LDH
Lactate Dehydrogenase (LDH, LD) is an enzyme found in any cell that metabolized glucose. It is therefore found in most tissues. An increase in the LD commonly indicates inflammation in the liver or muscle or destruction of red cells.
LDH ISOENZYMES
When the LD (LDH) is increased and the cause is not clear the LDH isoenzyme test may be carried out to determine which tissue is affected.
|
Abnormality
|
Possible causes
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|
Increased LD1 LD2
|
§ Myocardial infarction
§ RBC hemolysis
§ Megaloblastic anemia
§ Renal infection
§ Seminoma and other germ tumours
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Increased LD2 LD3 LD4
|
§ High correlation with malignancy
§ Massive platelet destruction
§ Pulmonary embolism
§ Lymphatic system involvement
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Increased LD3
|
§ Lung
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Increased LD5
|
§ Liver
§ Skeletal Muscle
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Isomorphic pattern (normal distribution with total LD elevation – all fractions increased)
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§ Cardiac
§ Musculoskeletal
§ Neoplasia
§ Multisystem disease
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|
Abnormal isoform
|
§ Genetic variant in amino acid structure or even loss of one chain
§ IgG autoantibody complex. If the autoantibody is against one chain it will give a graded pattern
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LEUCOCYTE ALKALINE PHOSPHATASE
Leucocyte Alkaline Phosphatase is present in the granules of neutrophils. The amount can be measured as the LAP score. Stimulated neutrophils have higher concentrations. LAP is decreased in CML and the LAP score has been used to distinguish CML from reactive neutrophilia and other myeloproliferative syndromes. Increased values are seen in neutrophil response to infection, inflammation, tumor, necrosis; polycythemia, agnogenic myeloid metaplasia, and essential thrombocythemia. Decreased values are seen in chronic myelogenous leukemia (CML), some myelodysplastic syndromes, acute myelogenous leukemia (AML), paroxysmal nocturnal hemoglobinuria (PNH), idiopathic thrombocytopenic purpura (ITP), pernicious anemia, and infectious mononucleosis.
LH
Luteinizing Hormone is made by the pituitary gland. It controls the production of Estrogen in the ovary and Testosterone from the testes. It is elevated in ovarian failure (menopause) or testicular failure. It is low in pituitary insufficiency.
LIPASE
Lipase is an enzyme produced by the pancreas to facilitate fat digestion. In pancreatitis (an inflammation of the pancreas causing severe abdominal pain) the lipase increases.
LITHIUM
Lithium is a drug that is used for the treatment of manic-depressive (bipolar) disorders. Effective medication with Lithium is adjusted by measuring its level in serum.
M
MAGNESIUM
Magnesium is an element that is necessary for many metabolic functions (an enzyme co-factor). Its reduction may occur in gastrointestinal and nutritional disorders.
MALARIA
Malaria is a parasitic infection of the red cells that is transmitted by mosquitoes in equatorial countries. It is diagnosed by careful examination of the blood with a microscope. Malaria is not just a tropical disease, it is becoming increasingly common in Canada due to travelling.
MERCURY
Metallic mercury (Hg) is essentially nontoxic, and may be consumed orally without significant side effects. Inhaled Hg vapor, however, can lead to both chronic and acute intoxications through chemical modification to the ionized (Hg2+) species. Further conversion to methyl mercury results in a high toxic species with a preference for fatty tissues and nerve cells. Small amounts of mercury are released from dental amalgams but this level of exposure is not considered significant. The most significant source of mercury exposure for most persons is seafood, especially with larger predatory fish (e.g. tuna, swordfish) or long-lived species (e.g. rock cod).
MICRO ALBUMIN
Microalbumin is not “small albumin” - it is “small amounts” of albumin in the urine. It is an important test to be carried out annually in all diabetics in order to detect kidney disease while it can be treated. For more information, please see the section on Diabetes.
MICROSOMAL AB
Microsomal antibodies are antibodies to thyroid tissue (thyroid antibodies). They are commonly increased in low amounts in normal people. However, low level increases may also mean that thyroid disease is present. High levels indicate thyroid disorders such as Thyroiditis.
MONO TEST
The mono test is important for diagnosis of infectious mononucleosis. For more information, please see the section on Mononucleosis.
MORPHOLOGY
The blood morphology examination is done by examining a smear of blood on a glass slide using a microscope. It is done when results of the Hematology Panel (Profile) are abnormal. It more clearly identifies the nature of the abnormality. For more information, please see the section on the Hematology Profile.
N
O
OCCULT BLOOD
Occult blood means unseen blood. It is a test carried out on feces as a way of detecting the presence of a bowel lesion such as cancer of the colon. For more information, please see the section on Colon Cancer.
OSTEOCALCIN
Osteocalcin is a hormone that increases in proportion to bone formation. It is used to study bone metabolic disorders. For more information, please see the section on Osteoporosis.
OVA & PARASITE
The O&P test is carried out by examining feces (stool samples) looking for worms or other abnormal organisms that may be the cause of diarrhea or malabsorption.
P
PHENOBARBITAL
Phenobarbital is a drug used for the treatment of seizure disorders. Adjustment of the appropriate dosage is made by measuring the drug in serum. For more information, please see the section on Therapeutic Drug Monitoring.
PHENYTOIN
Phenytoin is an anticonvulsant drug. Adjustment of the appropriate dosage is made by measuring the drug in serum. For more information, please see the section on Therapeutic Drug Monitoring.
PHOSPHOROUS INORGANIC
Phosphorus is an element that is needed in almost every cell. It is closely linked to calcium metabolism and this is the main reason why it is measured.
Phosphorus is present in the body in two basic forms: (1) bound to organic molecules (such as ATP) where it often serves to provide energy transfer, and (2) in a more free, ionic form as phosphate ion (PO4). This latter group is referred to as the inorganic phosphorus (or phosphate). Inorganic phosphate is closely associated with acid-base balance, calcium metabolism, and glucose flux into cells. Increased values are seen in: compensation for primary hypocalcemia (hypoparathyroid), hypercalcemia of rapid bone resorption, renal disease. Decreased values are seen in: compensation for primary hypercalcemia (1° hyperparathyroidism), post-glucose ingestion or insulin administration, and Fanconi’s syndrome of the proximal tubule.
PINWORM
Pinworms are tiny, almost microscopic worms, which infect the anal area and cause itching. They can be identified under a microscope. The collection of the sample is done using tape fixed to a microscope slide.
PLATELET COUNT
Platelets are tiny, round cells found in the blood stream. They have the ability to stick together and form tiny “plugs” in any damage to blood vessels. Thus, they are necessary to stop bleeding. Low levels of platelets indicate a bleeding or bruising tendency. High levels are associated with unwanted blood clot formation. Platelets may be normal in amount but may sometimes function abnormally. This problem requires special tests to diagnose. For more information, please see the section on the Hematology Profile.
POTASSIUM
Potassium is an important element that is necessary for proper cell membrane activity. Too much potassium causes cells to “twitch” inappropriately and if high enough may cause the heart to go into an arrhythmia. Low potassium may cause muscle weakness and paralysis. Increased values are seen in nondisease factors (exercise, pregnancy, posture, platelet destruction), hyperventilation; drugs -- potassium supplements (increase k intake), salt substitute (increase k intake), potassium-sparing diuretics, spironolactone (aldosterone antagonist), triamterine (blocks Na channels) , amiloride (blocks Na channels), non-steroidal anti-inflammatories (decrease activity of renin/aldosterone system and decrease renal blood flow and filtration), ACE inhibitors (decrease aldosterone and decrease renal blood flow and glomerular filtration), b-blockers (decrease potassium movement into cells and decrease renin/aldosterone activity), heparin (decrease aldosterone synthesis), digoxin intoxication (decreases Na-K ATPase), and trimethoprin (blocks Na-channels). Decreased values: decreased values in conjunction with hypertension; primary hyperaldosteronism, hyperdeoxycorticosteroidism, DOC producing adrenal tumours, congenital adrenal hyperplasia (11—hydroxylase deficiency and 17-hydroxylase deficiency), secondary hyperaldosteronism, antihypertensive therapy, ethanol abuse and withdrawal, coexistent NaCl deficiency or loss, hypovolemia, renovascular hypertension, pheochromocytoma, Cushing’s syndrome, primary hyperreninism. ectopic causes: renin secreting renal tumour, exogenous mineralocorticoid, high dose cortisol therapy, fludrocortisone, 9-a-fluoroprednisolone, carbenoxolone, licorice, chewing tobacco, other exogenous mineralocorticoids, 18-OH-DOC, 19-nor-DOC, abnormal steroid metabolites, and Liddle’s syndrome.
PREGNANCY TEST
The pregnancy test detects the presence of Chorionic Gonadotropin in serum or urine. It is turned positive by pregnancy, by rare tumors, or (in 1:100 people) by peculiar antibodies in the serum. It is positive within 24 hours of a pregnancy being established. Sometimes a pregnancy occurs but is “lost”. The pregnancy test may stay positive for some days. For more information, please see the section on Tests in Pregnancy.
PRIMIDONE
An anticonvulsant that is measured in the serum to adjust its dosage. For more information, please see the section on Therapeutic Drug Monitoring.
PROGESTERONE
Progesterone is normally present in low levels and then rises during the latter third of the menstrual cycle if ovulation has occurred. Thus, the test may be used to determine if ovulation is actually occurring.
PROGESTERONE, 17OH
17OH Progesterone is made by the adrenal gland. It is raised if there is an internal malfunction of adrenal metabolism. In such cases, the adrenal may manufacture excessive androgens. Thus, the test is used to investigate hirsutism (excessive body hair in women).
PROLACTIN
Prolactin is a pituitary hormone whose purpose is to mediate lactation following delivery. It is elevated in certain tumors of the pituitary gland in both men and women. Increased values are seen in: pregnancy and lactation, prolactin secreting adenomas (values over 6000 are almost always prolactinomas), non-functional tumours of the hypothalamus: craniopharyngioma, germinoma, cranial irradiation pituitary pathology (acromegaly, functional stalk section (pseudo-prolactinoma), empty sella syndrome, pituitary stalk section (trauma)), certain drugs ( neuroleptics: fluphenazine, haloperidol; anti-emetics: metoclopramide, domperidone; antidepressants: imipramine, amitriptyline, and methyldopa, opiates, estrogens, cimetidine. miscellaneous causes include: renal disease, surgical stress, sleep, exersize, sexual intercourse, hypoglycemia, post epileptic siezure, breast stimulation and chest lesions, primary hypothyroidism, cirrhosis, spinal cord disease. Reduced values have no clinical significance but may be caused by bromocriptine.
PROTEIN ELECTROPHORESIS
Protein electrophoresis is a chemical technique that is carried out to identify abnormal proteins in the serum (multiple myeloma – Link to Cancer – Multiple Myeloma) or to identify abnormal amounts of normal proteins.
PROTEIN, TOTAL
Total protein measurements determine the amount of all the proteins in serum. This test is used in conjunction with measurements of albumin or with protein electrophoresis to study deficiencies or over production of serum protein production.
PROTHROMBIN TIME
International Normalized Ratio (also known as the Prothrombin Time) is a test that measures defects in part of the clotting mechanism. It is used to detect clotting abnormalities. However, it is mainly used to measure the effect of “blood thinning” medications such as Warfarin our Coumadin. For more information, please see the section on Anticoagulant Monitoring.
PSA
The Prostate Specific Antigen is used to detect the presence of prostatic carcinoma or to monitor the effect of therapy. For more information, please see the section on Prostatic Cancer.
PTH
Parathyroid hormone is the main control of calcium in the serum. It is measured to determine why the calcium level is abnormal.
PTT
The activated Partial Thromboplastin Time is a test of the clotting mechanism of the blood. It is used in the diagnosis of bleeding disorders. If abnormal (prolonged), further testing is warranted to identify the specific disorder.
Q
R
RRA
The Rheumatoid Arthritis test (or Rheumatoid Factor = RF) is used to diagnose Rheumatoid arthritis. For more information, please see the section on Rheumatoid Arthritis.
RENIN
Renin is an enzyme hormone produced by the kidney that controls blood pressure. It should not be confused with rennin that is an enzyme found in milk. Excessive production of renin (certain kidney diseased, blood vessel blockage, and extraordinarily rare tumors) will cause a form of high blood pressure.
RETICULOCYTE COUNT
Reticulocytes are newborn red cells. An increased number of reticulocytes in blood indicates that red cells are being formed faster than normal.
RH FACTOR
All red cells have a “type” (A, B, AB, and O) and also may be classified as Rh+ or Rh-. Knowing this is important for pregnant women since Rh- women may develop antibodies that can harm a Rh+ baby unless treatment is undertaken.
ROUTINE CULTURE
When a bacterial infection is considered, the potentially infected area is swabbed and the swab sent to the lab. The lab then grows any bacteria that are present, determines whether they are harmful (pathogenic), and determines the antibiotics that will treat the infection most effectively.
S
SALICYLATES
Salicylate is the compound that aspirin is made from. Salicylate measurements are carried out when people take high doses of Aspirin for long-term therapy or when an overdose of Aspirin is suspected.
SEMEN EXAMINATION
Semen is examined as part of an infertility work-up. The sample is examined for the presence of spermatozoa, how many are present (the count), the number of abnormal forms present, and whether they move quickly or not (motility). The nature of the fluid itself is also examined. To be performed properly the sample must be as fresh as possible. Semen is also examined following a vasectomy to determine whether it is “complete” or not. In this case, only the presence or absence of sperm is noted (and if present, a count is made).
SICKLE CELL TEST
Sickle cell anemia is a condition that mainly affects people of African descent. The red cells of these people “crumple up” if the oxygen level gets too low. The cells, under a microscope, become sickle shaped (rather than being dimpled spheres).
SODIUM
Sodium is the major ion in the serum. Abnormalities in sodium concentration cause blood pressure abnormalities and edema and may be due to hormonal or to kidney disease. Increased values are seen in dehydration, IV fluids administration, posterior pituitary disease, adrenal disease, and kidney disease. Decreased values are called hyponatremia and are seen in overhydration, renal disorders, cardiac failure, pituitary and adrenal disorders, and excessive glucose or lipids.
T
T4
Thyroxine (T4) is the main thyroid hormone. It is raised in hyperthyroidism and low in hypothyroidism. It may be altered by variations in the thyroid binding protein (TBG). It is a secondary test in thyroid diagnosis, the first test being the TSH. For more information, please see the section on Thyroid Disease.
T4, FREE
Free thyroxine (FT4) is measured by a special technique that avoids the influence of thyroid binding protein (see T4). For more information, please see the section on Thyroid Disease.
TESTOSTERONE
Testosterone is the main male hormone. In men, low testosterone causes impotence. In women, elevated testosterone causes hirsutism (excess hair) or even virilization (in cancers). In women, low testosterone may be the cause of loss of libido. The testosterone measurement may be confused by alterations of the Testosterone Binding Protein (SHBG).
TESTOSTERONE, FREE
Free testosterone is a special technique that measures the testosterone concentration without being influenced by its binding protein (SHBG). See Testosterone. The Free Testosterone is equivalent to the Bioavailable Testosterone.
THALASSAEMIA INVESTIGATION
Thalassemia is the abnormal production of otherwise normal hemoglobin molecules. It is covered in more detail in another section. Link to Hematology - Thalassemia
THEOPHYLLINE
Theophylline is an asthma drug. It can be measured to enhance the dosage regime. For more information, please see the section on Therapeutic Drug Monitoring.
THROMBIN TIME
The Thrombin Time is a test of the clotting mechanism of the blood. It is employed in work-ups of blood coagulation disorders.
THYROGLOBULIN
Thyroglobulin is a protein found inside the thyroid gland that helps to store thyroid hormone until it is needed. It is detected in the serum with certain thyroid cancers and is used to monitor the success of therapy of these conditions.
THYROGLOBULIN AB
Thyroglobulin antibodies are sometimes increased in thyroid inflammation (Thyroiditis). They are also measured to ensure that Thyroglobulin assays are accurate.
TRANSFERRIN
Transferrin is a protein that carries iron in the blood stream. It is used as a secondary test of iron metabolism (ferritin is used first). It is always done in conjunction with serum iron measurements where it is termed iron-binding capacity. Another calculated result is the percent saturation. This is the extent to which transferrin is coated with iron. For more information, please see the section on Hemachromatosis.
TRICHOMONAS WET MOUNT
Trichomonas is a microorganism that infects the genital region. It is detected by collecting a drop of fluid and examining it under a microscope.
TRIGLYCERIDES
Triglycerides are fats that circulate in the blood stream. They are different from cholesterol (olive oil is a triglyceride). Their measurement is important in gaining a “picture” of the blood fat (lipid) content. For more information, please see the section on Cholesterol.
TSH
Thyroid Stimulating Hormone (TSH) is produced by the pituitary gland and it controls the thyroid gland. It is the main thyroid function test and goes up in hypothyroidism and down in hyperthyroidism. For more information, please see the section on Thyroid Disease.
U
UREA
Urea is a waste product of protein metabolism. It is removed from the body by the kidney. Its measurement is used as a test of kidney function because when the kidney is impaired, levels of urea go up. It is also known as the BUN.
URIC ACID
Uric acid is a waste product of nucleic acid (DNA, RNA) metabolism. It is elevated in gout, kidney disease and in conditions where body tissues degenerate rapidly.
URINALYSIS
Urinalysis is a common screening test wherein a urine sample is tested for several chemical substances (glucose, protein, etc.) and is then examined under a microscope (to look for cells, etc.). This test is covered in more detail elsewhere. For more information, please see the section on Urinalysis.
URINE AMYLASE
See “Amylase”. The urine amylase increases in pancreatitis.
URINE CALCIUM
The urine calcium is measured to determine if the body is losing more calcium than normal. High urine calcium also poses a risk for calcium kidney stones.
URINE COPPER
Urine copper is measured rarely as a secondary test in a work-up for Wilson’s Disease. See “Ceruloplasmin”.
URINE CREATININE
Urine creatinine is a waste product of muscle metabolism. It is measured to gauge how complete a urine collection is or to ratio other urine constituents against.
URINE HEMOSIDERIN
When the plasma Hb exceeds 5 g/L, the capacity of haptoglobin and hemopexin to “mop it up” may be exceeded and the free hemoglobin passes through the glomerulus and into the kidney tubule. Some hemoglobin enters the urine as free hemoglobin. The hemoglobin is absorbed by the proximal tubule and converted into hemosiderin. When the PCT cells are shed into the urine, hemosiderinuria occurs.
URINE HIAA
5-HIAA is produced in excess and can be measured in the urine by an unusual tumor of the intestine known as a carcinoid. The presence of a carcinoid tumor may cause unusual symptoms of hot flushes, hypertension and a tricuspid valve heart murmur.
URINE MAGNESIUM
Measuring urine magnesium is a way of determining magnesium storage in the body.
URINE MERCURY
Excess amounts of urine mercury demonstrate recent (past two weeks) exposure to mercury.
URINE METANEPHRINES
A rare tumor of the adrenal gland secretes a number of adrenaline related metabolites that can be detected in the urine. Metanephrines are amongst these substances. See more detailed discussion.For more information, please see the section on Adrenal Disease.
URINE MICROSCOPIC
Part of urinalysis wherein the urine is examined under a microscope. See detailed discussion. For more information, please see the section on Urinalysis.
URINE OXALATE
Oxalate is a metabolic end product that is excreted into the urine. High levels may cause calcium oxalate stones to form. Two causes of increased oxalate are intestinal disease and rare inborn errors of metabolism.
URINE PHOSPHOROUS
Urine phosphorus is measured as a secondary test to understand calcium metabolism.
URINE PORPHOBILINOGEN
In the inherited disorder known as Acute Intermittent Porphyria patients suffer excruciating abdominal pain and produce excessive amounts of porphobilinogen in their urine.
URINE POTASSIUM
The urine potassium level indicates how much potassium you are ingesting in your diet (as long as the serum level is normal). If you have abnormal serum potassium, a urine measurement will help determine the cause.
URINE PROTEIN
Normally only a small amount of protein is found in urine. Excessive amounts are seen in kidney disease.
URINE PROTEIN ELECTROPHORESIS
Urine protein electrophoresis is a chemical technique that is carried out to determine what type of protein is present in abnormal amounts. It also is the way myeloma proteins are measured in the urine. For more information, please see the section on Multiple Myeloma.
URINE SODIUM
Urine sodium is a function of the sodium in the diet.
URINE URIC ACID
Urine uric acid is raised in gout and in rapid cell breakdown and in some people who simply excrete too much. A high urine uric acid is a risk factor for uric acid stone formation.
URINE VMA
VMA is increased in the urine in stress and in a rare tumor that causes hypertension and episodes of sweating called a Pheochromocytoma. For more information, please see the section on Adrenal Disease.
UROBILINOGEN
Usually detected as part of routine urinalysis. For more information, please see the section on Urinalysis.
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Condition
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Urine Bilirubin
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Urine Urobilinogen
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Normal
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Negative
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Negative
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Hemolysis
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Negative
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Positive
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Obstruction to bile flow
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Increased
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Negative if complete
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Cholestasis
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Increased
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Decreased early, increased late
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Hepatocellular damage
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Increased
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Decreased early, increased late
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V
VALPROIC ACID
An anti-epileptic drug. Serum measurements help with dosage adjustment. For more information, please see the section on Therapeutic Drug Monitoring.
VISCOSITY
In certain conditions (macroglobulinemia, myeloma) the blood becomes thick and sluggish. Viscosity measurements quantitate this abnormality.
VITAMIN B12
Vitamin B12 deficiency may lead to macrocytic anemia and to neurological degeneration of part of the spinal cord.
VITAMIN D
Vitamin D is required for normal bone formation. Vitamin D is a sequence of molecules in which several steps increase the potency of the hormone to absorb calcium from the gut, retain calcium at the kidney and facilitate the action of parathyroid hormone. The starting material is calciferol (found in grains). After absorption (fat soluble) it must be irradiated by sunlight on skin to convert it into the a more active form. Certain foods provide this form directly (i.e. cod liver oil). This molecule then passes through the liver where it is converted to 25-hydroxy-cholecalciferol (25-OH D). This in turn, passes through the kidney where it is converted into the very active form 1,25-diOH vitamin D.
Increased values of 25 OH-vitamin D are seen in vitamin D intoxication and abundant sunlight. Decreased values are seen in: malabsorption, dietary osteomalacia, steatorrhea, biliary or portal cirrhosis, anticonvulsant osteomalacia, some cases of renal osteodystrophy, osteitis fibrosa cystica, thyrotoxicosis, hyperparathyroidism, hypopituitarism, and chronic renal failure.
Increased values of 1,25 diOH-vitamin D are seen with tumoural calcinosis, primary hyperparathyroidism, sarcoid, normal children, pregnancy, and lactation. Decreased values are seen with chronic renal failure, uremia, pseudohypoparathyroidism, vitamin D dependent rickets, postmenopausal osteoporosis, tumour induced osteomalacia, adolescents with insulin dependent diabetes mellitus, and is not detectable in anephric patients.
W
WBC
White Blood Cell count is part of the routine Hematology Panel.
X
Y
YEAST
Yeast, such as Candida albicans can cause infections of the mouth or genitalia. The microbiology lab can detect the presence of yeast. Although there is much non-medical information about yeast in the blood, this is something that only occurs in rare situations (patients who are gravely ill).
Z
ZINC
Zinc is not very toxic. However, true zinc deficiency may lead to the failure of wounds to heal properly.
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