Tissue Transglutaminase (TTG)

Department of Immunology

Indication

Highly sensitive and specific test for coeliac disease or dermatitis herpetiformis.

Notes

• This is the primary screen for coeliac disease. Confirmatory IgA anti-endomysial (AEA) will be automatically added on all positives.
• The assay has a built-in check for IgA deficiency. If IgA<0.2g/L the sample will be referred to Southmead hospital for IgG endomysial antibodies testinh.
• In children a TTG of >100 is highly suggestive of coeliac disease, so a biopsy may not be necessary.
• TTG requests will not routinely be processed within a year of a previous negative result.
• Serological assays for the investigation of coeliac disease are only accurate if the patient is on a gluten containing diet, e.g., gluten present in >1 meal a day, for >6 weeks prior to testing.

Sample Requirements

(No patient preparation or special handling required).

Adult

5ml Gold-top SST tube or 3.5ml Rust-top gel tube (Trust users only)

Paediatric

1ml Serum Sample

Turnaround Times

7 days

Time Limit for Add-ons

3 days