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Test Directory -  Coeliac Screen



tTG, tissue transglutaminase, anti gliadin antibodies, anti-endomysial antibodies

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 for confirmation as per recent guidelines.

Test Includes

Detection of IgA autoantibodies against tissue Transglutaminase. This is the primary Coeliac Disease screening test and requests for anti- endomysial or anti-gliadin antibodies will be screened for the presence of anti tTG IgA.

Request Form

Combined Pathology Blood form (Yellow/Black)


Analysed by referral laboratory


Specific criteria




Patient preparation


None required




IgA tTG antibody will be negative in IgA deficient individuals (as will the IgA anti gliadin antibody and IgA endomysial antibody). IgG tTG will be assayed in these cases.

Turnaround Time

2 weeks




2 ml


Yellow top (SST) tube or

paediatric brown top

Causes for Rejection


Assay within previous 3 months

Reference range


Negative: less than 7.1 U/mL
Equivocal: 7.1 - 10.0 U/mL
Positive: greater than 10.0 U/mL


IgA tTG antibody provide the most sensitive (~90%) and specific (96%) marker for coeliac disease. IgA deficient patients are further tested for IgG tTG to confirm or rule out coeliac disease.

Lab handling


Processing: Immunology at the Hub laboratory

Version 1.1 / Feb 2016                                                                                                                Approved by: Consultant Biochemist