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Interpretive Handbook

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Test 88906 :
Celiac-Associated HLA-DQ Alpha 1 and DQ Beta 1 Medium-High Resolution DNA Typing, Blood

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Celiac disease (gluten-sensitive enteropathy) is mediated by T lymphocytes in patients with genetic susceptibility. This genetic association is with certain HLA genes in the class II region (DQ alpha 1, DQ beta 1).

 

For your convenience, we recommend utilizing cascade testing for celiac disease. Cascade testing ensures that testing proceeds in an algorithmic fashion. The following cascades are available; select the appropriate 1 for your specific patient situation. Algorithms for the cascade tests are available in Special Instructions.

-CDCOM / Celiac Disease Comprehensive Cascade: complete testing including HLA DQ typing and serology

-CDSP / Celiac Disease Serology Cascade: complete testing excluding HLA DQ

-CDGF / Celiac Disease Gluten-Free Cascade: for patients already adhering to a gluten-free diet

To order individual tests, see Celiac Disease Diagnostic Testing Algorithm in Special Instructions.

Useful For Suggests clinical disorders or settings where the test may be helpful

Assessing risk of celiac disease

Interpretation Provides information to assist in interpretation of the test results

Most (90%-95%) patients with celiac disease have the DQ2 allele (encoded by DQA1*05 and DQB1*02), while the remainder have DQ8 (encoded by DQA1*03:01 and DQB1*03:02). Rare exceptions to these associations have been occasionally seen. In 1 study of celiac disease, only 0.7% of patients with celiac disease lacked the HLA alleles mentioned above.

 

It is important to realize that these genes also are present in about 20% of people without celiac disease. Therefore, the mere presence of these genes does not prove the presence of celiac disease or that genetic susceptibility to celiac disease is present.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

No significant cautionary statements

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Clinical References Provides recommendations for further in-depth reading of a clinical nature

Polvi A, Arranz E, Fernandez-Arequero M, et al: HLA-DQ2-negative celiac disease in Finland and Spain. Hum Immunol 1998 Mar;59(3):169-175


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