HLA-DQ2/DQ8

Diagnostic Use

IMPORTANT UPDATE 30/04/2025: Due to an unforeseen equipment failure we are currently unable to process samples for this testing. The timeline to resume testing is unknown at this stage.

Alternative options for testing are the NZ Blood Service in Auckland, Awanui Wellington or Sonic Genetics in Australia.

We apologise for this disruption to our service.

Symptoms of gluten intolerance and/or elevated risk for coeliac disease.
Raised TTG, with symptoms of celiac disease.
Asymptomatic people at HIGH-RISK of coeliac disease (eg: sibling of CD case, for further information see PMID: 25827511).

Department

Genetics - Molecular Pathology

Delphic Registration Code

MOLP

Constituent Tests

• Tissue Transglutaminase IgA antibodies
• Tissue Transglutaminase IgG antibodies

Synonyms

Coeliac Gene Screen
DQ typing for coeliac disease
HLA-DQ

Turnaround Time

4 weeks

Test Code

7032

Specimen Type

• Whole Blood

Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Acceptable

• EDTA (Lavender Cap)

Preferred Sample Volume (ml)

4.0

Minimum Sample Volume (ml)

0.5

No of Samples Required

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred

• EDTA (Lavender Cap)

Acceptable

• EDTA (Lavender Cap)

Preferred Sample Volume (ml)

1.0

Minimum Sample Volume (ml)

0.5

Additional Specimen Information

If storing blood tube prior to delivery please refrigerate at 4 degrees (transport still at ambient temperature).
This test requires nucleated cells. Please do not centrifuge or freeze blood samples.

Aliquot Instructions

Sample Type

• Whole Blood

Transport to Lab

Ambient (8 - 24 degrees Celsius)

Interpretation

The presence or absence of coeliac disease-associated HLA-DQA1 and HLA-DQB1 alleles (DQ2.2, DQ2.5 and DQ8) are reported, along with the relative risk (as per the figure below). The distinction between the homozygous or heterozygous presence of the alleles, which encode the alpha- and beta-subunits of HLA-DQ2.2 and HLA-DQ2.5, allows for improved risk stratification.

The presence of a risk allele does not confer a diagnosis of coeliac disease and has low positive predictive value. Supportive evidence from coeliac serology and small intestinal histology is necessary for the diagnosis.

The absence of HLA-DQ2 and HLA-DQ8 may serve to exclude a diagnosis of coeliac disease (likelihood of coeliac disease <1%).

Test Method

This molecular genetic test uses the Euroimmun HLA-DQ2/DQ8 reverse dot blot array to determine the status of the disease-associated HLA-DQA1 and HLA-DQB1 alleles in a patient with possible celiac disease. Briefly, allele-specific primers are used to PCR amplify several sections of the HLA-DQA1 and HLA-DQB1 genes from the patient’s DNA. Once amplified, the allele-specific PCR products are hybridised to an array containing immobilised oligonucleotide probes, homologous to the amplified alleles. Only those alleles successfully amplified, and therefore present within a patient’s DNA, will hybridise and emit florescence at the particular allelic probe.

Non-Funded Test Cost

$106.34 (Exclusive of GST)

Billing Code

7032

Contact Information

Enquiry Form