UPDATE ON LABORATORY TESTING FOR DIAGNOSIS OF COELIAC DISEASE(CD)
Currently our testing profile has consisted of IgG Gliadin antibodies, IgA Gliadin antibodies and a single Tissue Transglutaminase IgA antbody test.
These two IgG and IgA Gliadin tests have now been replaced by a single IgA test using a new deaminated Gliadin.
The present Tissue Transglutaminase IgA antibody test (TTG IgA) is being supplemented with an additional Tissue Transglutaminase IgG antibody test (TTG IgG).
Our new test profile for Coeliac Antibodies will be :-
- TTG IgA,
- TTG IgG
- Gliadin (Deaminated) IgA.
We believe that these three tests will offer an increased sensitivity and specificity and in addition will catch the small number of patients with CD who are IgA immunodeficient.
In particular we expect to see a very significant reduction in the number of false positive Gliadin antibody tests without loss of screening sensitivity for CD.
Monitoring of dietary compliance will be unaffected.
As before, we strongly recommend that all newly diagnosed cases are confirmed by duodenal biopsy.
ESR REQUESTS
Over the years, our laboratory instrumentation has evolved to reduce contact with blood. ESR’s has been a manual test, where the possibility of blood contamination to the laboratory staff is high. We have moved to a semi-automated method that is safer. We will be phasing out the Black top ESR tubes and encourage the use of one EDTA Lavender top tube (Same as Full Blood Count). When a FBC & ESR is requested, please take two Lavender top tubes.
BREAST CANCER GENETIC TEST
We are getting quite a few requests for the BRCA2 gene test for Breast Cancer. The testing for this is done in Melbourne by the Peter McCallum Clinic, and their Laboratory will not accept samples unless the patient has been counselled by the Tasmanian Genetic Counselling Service. The contact is Jo Bourke in Hobart on (03) 6222 8296.
CHANGE IN IMMUNOASSAY INSTRUMENTATION
As a result in an upgrade in instrumentation / assays reference ranges for Thyroid Function Tests differ from those previously reported; reference ranges for CEA, CA125 and HCG are unchanged, however caution should be exercised in comparing numerical values from the new assays with previous values as patient comparison studies have demonstrated some values for CEA and CA125 may be up to 30% higher with the new method, and HCG values are generally lower than those reported with the previous method.
If you require any further information please do not hesitate to contact Dr Michael Beamish or Paul Stancombe on 63 34 3636