IgA anti-TTG is the primary screening test for Coeliac Disease and Dermatitis Herpetiformis.
IgA TTG - Fluorescence Enzyme Immunoassay (FEIA)
Calibration: Traceable to the International Reference Preparation (IRP) 67/86 of Human Serum Immunoglobulins A, G and M.
Must not be on gluten free diet
Patients with IgA deficiency will give falsely negative results.
Testing method used will be able to detect IgA deficiency. If samples are found to be IgA deficient, an automatic testing cascade for measurement of (high sensitive) total IgA and IgG anti-TTG will be performed.
Patients must be on a gluten containing diet when tested.
Serum is the only validated sample type
Coeliac screen should be requested as TTG.
Ambient (8 - 24 degrees Celsius)
200 uL serum (minimum),1 mL serum (preferred)
IgA antibodies to TTG are useful in the diagnosis and follow-up of coeliac disease. They are highly disease specific markers for untreated coeliac disease providing patients are on a normal (gluten containing) diet.
Some controversy exists over optimal testing strategy for patients with suspected coeliac disease. Current practice tests IgA anti-TTG as the first line followed by IgA endomysial antibodies if IgA anti-TTG are equivocal or positive.
In adults it is recommend that patients with positive titres be referred for specialist clinical assessment and confirmation by small bowel biopsy before any treatment is undertaken.
Children with positive TTG above 10x upper limit of normal may be eligible for biopsy-free diagnosis of coeliac disease pending further serological testing and Paediatric Gastroenterology confirmation. Small bowel biopsy remains the gold standard for diagnosis of coeliac disease in relevant children with positive TTG below 10x upper limit of normal. Recommend referral to local Paediatrics/Paediatric Gastroenterology service for further assessment.
Patients with IgA deficiency will give negative results, therefore, testing for IgG TTG is useful and will be automatically testing where IgA deficiency is detected.
Anti-TTG may be useful in monitoring dietary compliance.
Negative = < 7 units
Equivocal = 7-10 units
Positive = > 10 units
Fluorescence Enzyme Immunoassay (FEIA)
$43.13 (Exclusive of GST)
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