Test Catalog

Test

Code
X800
Name
CELIAC GENOTYPE
Notes
Description

Also known as: HLA TYPING FOR CELIAC DISEASE, HLA DQ2/DQ8, CELIAC DISEASE GENOTYPING, HLA GENOTYPING FOR CELIAC DX, HLA-DQ HLA-DQ2 HLA-DQ8, HLA-DQA1*05 HLA-DQB1*02 & *03, HLA-DQA1 HLA-DQB1, HLA GENOTYPING FOR CELIAC DX, HLA TYPING FOR CELIAC DISEASE, CELIG, X800
Orderable Code: X800
Test Contains (LOINC): HLA-DQA1 (44728-4), HLA-DQB1 (43291-4), Serologic Equivalent, Celiac Interpretation
SPECIMEN REQUIREMENTS
Sample Type: Whole Blood
Preferred Container: EDTA (Lavender Top) Tube
Sample Volume: 3.0 mL
Minimal Sample Volume: 1.0 mL (does not allow for repeat testing)
Handling Instructions:
Refrigerate specimen after collection.
Client Transport Temperature: Refrigerated
Specimen Stability: Ambient: 7 Days; Refrigerated: 1 Month; Frozen: 1 Month
Unsuitable Specimen: Heparinized specimens
TESTING
Frequency: Monday, Wednesday, Friday
Expected Turn Around: 6 – 8 Days
Responsible Dept: Reference Lab
Referral Lab: SRL
Referral Lab Code: X800
CPT: 81376 X 2
Methodology: PCR and sequence specific oligonucleotide (SSO) probes
ADDITIONAL INFORMATION:
Celiac disease (CD) is a chronic autoimmune disease characterized by gastrointestinal and/or non-gastrointestinal manifestations due to the ingestion of gluten in genetically predisposed individuals. Gluten is the major storage protein found in wheat, barley, and rye and is comprised of two subcomponents: gliadin and glutenin. Pathogenesis of celiac disease is initiated by a gliadin induced localized inflammatory response and subsequent killing of enterocytes in the intestinal mucosa resulting in villous atrophy.
Celiac disease is usually characterized by failure to thrive, malnutrition, diarrhea, abdominal pain and distension within the first few years of life. Children may present with shortness of stature and/or delay of puberty due to nutritional deficiencies. Presentation of Celiac disease in later years is usually characterized with more subtle symptoms such as abdominal pain, diarrhea or constipation, bloating and excessive gas. Many patients are often misdiagnosed with diseases such as irritable bowel syndrome, Crohns disease, gastric ulcers, anemia, parasite infections, or nervous conditions and may have a number of procedures or hospital admissions due to symptoms prior to diagnosis.
The prevalence of CD in the general population in the United States is approximately 1%; however, the risk of disease increases up to 10% in individuals with first-degree relatives with CD. The risk can be even greater if multiple family members are affected.
The genetic susceptibility for CD is associated with the class II HLA genes (DQ alpha 1, DQ beta 1). About 90% of patients with CD will have one copy of the HLA DQ2.5 haplotype (DQA1*05 with DQB1*02:01 or DQA1*05 with DQB1*02:02) or two copies of the DQ2.2 haplotype (DQA1*02:01 with DQB1*02:02). The remaining CD patients have one copy of the DQ8 haplotype (DQA1*03, DQB1*03:02).
The presence of specific HLA haplotypes does not indicate that a patient will develop CD. 30-40% of the general population has a susceptible or permissive HLA haplotype. Only approximately 3% of people with a permissive HLA haplotype will develop CD. The absence of these alleles in an individual makes a diagnosis of CD unlikely.
Compliance Statement: FDA cleared or approved assay