ELECTRONIC REPORTING OF LABORATORY RESULTS VIA PATHNET 

MDS Metro and BC Biomedical Laboratories have developed PathNET, an electronic reporting system for laboratory test results. It offers access to historical lab result records, cumulative reporting and a number of other inter-active options to sort and manage your patient results. PathNET meets provincial standards for diagnostic information management and new privacy and confidentiality requirements.  

PathNET is available to you at no change and is now in use by over 650 physicians throughout the lower mainland. 

As a reminder, as of April 30th, 2002, MDS Metro and BC Biomedical Laboratories will no longer transmit laboratory results via Medinet. Should you choose not to use PathNET’s services, we will continue to provide the other result delivery options we have offered over the years, including fax, hand-delivery and mail. 

For more information about PathNET, please call 1-866-728-4777 or visit www.pathnet.ca.

PARENTAGE TESTING 

MDS Laboratory Services is pleased to announce the launch of a complete national DNA parentage testing service. All testing will take place at the Burnaby Reference Laboratory of MDS Metro. The methodology uses analysis of a group of Short Tandem Repeats (STRs); stretches of non-coding DNA that contain multiple copies of either four or five base pairs. The number of copies of the tetra- or pentanucleotide at each STR is highly variable within the population, making them ideal for identity testing.

To evaluate paternity, samples (buccal swabs or blood) are collected from the mother, child and alleged father. For each STR, results from the alleged father are compared with those of the child and mother. The data are assessed against the frequency distribution of STRs in the appropriate ethnic group. The cumulative results are used to develop a paternity index, the genetic odds in favour of paternity. Paternity can be confirmed or excluded with a high level of certainty.

Identity testing is also used in immigration cases, to prove that sponsoring parties and applicants are related, and to determine other familial relationships such as maternity or sibling relatedness.

As the testing is used for legal purposes, it does not require a physician requisition form and is private-pay. Individuals may obtain more information by contacting the MDS Customer Care Centre, toll-free at 1-877-849-3637, 24 hours a day. Specimens may be collected in one of our Patient Service Centres or another laboratory. Results are available 4 to 7 business days after the last sample is collected.

THE UREA BREATH TEST FOR HELICOBACTER PYLORI

The Urea Breath Test is now recognized as the definitive non-invasive method for the diagnosis of H.pylori infection. The UBT is now fully covered by the MSP and MDS Metro Laboratory Services will be offering the test as a funded service, effective February 25, 2002.

H.pylori infection is the main cause of peptic ulcer disease and gastritis. The organism has also been associated with gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma. The organism is found in 20-40% of Canadians and the prevalence increases with age. The lifetime risk of peptic ulcers in adults with H.pylori is approximately twice as much as persons without H.pylori.

The Guidelines and Protocols Advisory Committee (BCMA and Ministry of Health) have published a document entitled “Clinical Approach to Adult Patients with Dyspepsia” (www.healthservices.gov.bc.ca/msp).

This protocol suggests that patients with “alarm features” require prompt investigation with upper GI endoscopy and biopsy. Those patients who do not present with “alarm symptoms” have two options. Patients can be tested for H.pylori infection. If the test is positive, then antibiotic eradication is required. If the test is negative, empiric therapy consisting of a 4-week course of a histamine-2 receptor antagonist or a proton pump inhibitor is recommended. Alternately, but more complicated, the empiric therapy can be used as the initial approach with UBT to follow when appropriate.

The assessment of successful treatment for H.pylori is performed using the Urea Breath Test, six-weeks after the course of antibiotic therapy.

There are several tests for the diagnosis of H.pylori:

Serology: Serological tests detect the presence of antibodies to H.pylori. Positive serology indicates current or past infection with H.pylori. A positive test does not confirm active disease. A negative serological test provides >95 % assurance that there is no H.pylori infection. Serology should not be used in the evaluation of treatment of H.pylori because the antibody titre takes many months (or even years) to decline.

Urea Breath Test (UBT): The patient is asked to drink a dilute solution containing labelled urea. H.pylori contains urease, an enzyme that splits urea into CO2 and NH3. The CO2 is then absorbed into the bloodstream and rapidly exhaled in the breath. The presence of labelled CO2 in a breath sample has 98 % sensitivity and 99 % specificity for the presence of H.pylori.

Two labels have been employed. C-14 is a beta-emitting radioactive isotope with a half-life of over 5,000 years that is detected by beta-scintillation. C-13 is a non-radioactive, stable isotope that is measured by mass spectrometry.

Biopsy for culture and histology: Biopsy is considered to be the gold standard. However, it is invasive, expensive, and less sensitive (because of sampling errors and bacterial growth failures) than the UBT.

Other tests: Salivary antigen detection has been evaluated but found to have unacceptable accuracy for the diagnosis of H. pylori infection. A fecal antigen detection test has also been developed, but more experience with the test is needed to assess its clinical utility.

The best test:

The C-13 UBT has been recommended as a clinical gold standard against which other diagnostic methods can be validated. (Bazzoli) From February 25, all requests for H. pylori testing will be performed using the C-13 UBT unless serology is specifically indicated on the requisition.

In children under two years of age, the UBT may be difficult to administer and borderline results are common. Persons with end-stage chronic obstructive pulmonary disease cannot produce adequately mixed breath samples and should not be tested.

To evaluate the successful eradication of H. pylori a UBT test is recommended six weeks after antibiotic therapy has terminated. Undertaking the UBT prior to this time is associated with both false negative and false positive results.

The following may increase the risk of false negative UBT results, therefore, prior to testing, a patient must:

• fast and refrain from smoking for four hours,
• refrain from taking any Bismuth containing medication (e.g. Pepto-Bismol) for at least two weeks,
• refrain from taking H2 inhibitors for two weeks,
• refrain from taking proton pump-inhibitor (Losec, Prevacid, Pantoloc) for at least two weeks,
• refrain from taking antibiotics for at least one month, and
• wait six weeks after H. pylori treatment.

Patients are requested to book the test by contacting the nearest MDS Metro Patient Service Centre.

References:  

Veldhuyzen van Zanten SJO, et. al. An evidence-based approach to the management of uninvestigated dyspepsia in the era of Helicobacter pylori. Can Med Assoc J 2000; 162 Suppl 12: 3-23.

Bazzoli F, et. al. Urea breath tests for the detection of Helicobacter pylori infection. Helicobacter 1997; 2 Suppl: S34-7.

Fallone CA, et.al. The urea breath test for Helicobacter pylori infection; taking the wind out of the sails of endoscopy. CMAJ 2000 May 16; 162: 1401-2.

ALLERGY TESTING

The allergy season is approaching and requests for serum allergy testing (SAIGE) are increasing. We would like to remind you that MSP will pay for up to 20 allergens only if one or more of the following requirements is satisfied:

• debilitating symptoms unresponsive to usual management,
• a history of life threatening severe reactions, or
• generalized skin reactions that prohibit skin testing.

You are encouraged to use the special MDS Allergen Request Form.

Service questions can be directed to 1-800-663-9422.

Medical interpretations can be directed to Dr. Michael McNeely at 250-881-3109 or 604-878-0929.

Our Web Site www.mdsmetro.com

Visit us for specimen collection instructions, patient oriented discussions about common and rare disorders and lab tests.

DO YOU HAVE A QUESTION ABOUT OUR TESTING?
Email ASKDOC  and one of our subspecialists will provide an answer