Pathology Handbook

Coeliac screen

Synonyms

TTG
Tissue Transglutaminase

Test Includes

Detection of IgA autoantibodies against tissue Transglutaminase. 
This is the primary Coeliac Disease screening test and all requests for anti endomysial/gliadin antibodies will be screened for the presence of anti tTG IgA. In addition all children under the age of 16 will also have their serum IgA levels measured to detect IgA deficiency

Clinical Indications

Coeliac Disease
Dermatitis herpetiformis
Please note: The anti tTG IgA assay should not be considered diagnostic, but should be used in conjunction with all clinical and laboratory findings.
Samples found to be tTG IgA positive or equivocal will be tested for the presence of anti endomysial IgA. Samples found to be serum IgA deficient, or where laboratory findings serum IgA deficiency, will be presence of anti tTG IgG.

Request Form 

Request via ICE

Availability

Samples are tested daily Monday to Friday.

Specific Criteria

It is essential to give relevant clinical information

Turnaround Time

All tests are performed on the next routine working day after reciept of the sample.

Specimen

Serum

Volume

7 ml

Container

Red top tube.
Gold top (SST) tube will be accepted

Collection

Samples should be transported to the laboratory as soon as is practicably possible.

Causes for Rejection

Unlabelled/inadequately labelled sample
Inadequately completed request form
Delay in sample reaching laboratory

Lab Handling

Aliquot and store at 4-8°C prior to testing and at -20°C or below for up to 1 month after receipt.

Reference Range

Negative less than 7 U/ml

Equivocal 7-10 U/ml

Postive greater than 10 U/ml