tTG antibody

 

Alternative names, keywords

Tissue transglutaminase 2 antibody, endomysial antibody, coeliac disease, gluten enteropathy.

Samples required

Clotted blood (gold cap, 5 mL tube). Smaller tubes are available for paediatric samples.

Test indications

See NICE guideline NG20 - Coeliac disease: recognition, assessment and management.

Test information

Immunoassay for levels of IgA tTG2 antibody. IgA endomysial antibody will be performed automatically for all equivocal or positive samples.

Positive results are associated with coeliac disease. Strong positive results with positive endomysial antibody on two occasions may in some situations be used for biopsy-free diagnosis.

Negative results do not completely exclude coeliac disease.

Note that patients need to be taking dietary gluten for valid results. The recommendation is regular gluten for 6 weeks or more before testing.

Serial tests are useful for disease monitoring.

All samples are screened for possible IgA deficiency. There is no need to test IgA separately unless clinically indicated. IgA levels will be indicated only when low; if the levels are 0.2g/L or less, IgA tTG results will not be reported and we will organise IgG endomysial antibody automatically. Please note that minor degrees of IgA deficiency are not clinically relevant and do not affect the sensitivity of IgG tTG2 antibody.

Method:

IgA tTG2 antibody: Phadia 250 ELiA

IgA and IgG endomysial antibody: indirect immunofluorescence*

*Referred to Immunology, St Richard's Hospital, Chichester PO19 6SE.

 

Reference range

Negative < 7 U/mL
Equivocal 7-10 U/mL
Positive ≥ 10 U/mL

Turnaround time

IgA tTG 2 antibody: 7 days
IgA endomysial antibody:  14 days
IgG endomysial antibody: 28 days
 

Enquiries

Immunology