How can I get insurance to cover the cost of a gliadin (immunoglobulin) IgG/IgA test?

Getting Insurance Coverage for Gliadin IgG/IgA Testing

Gliadin IgG/IgA antibody testing is generally not recommended or reimbursed by insurance because these tests have been superseded by more accurate serologic markers for celiac disease, specifically tissue transglutaminase IgA (tTG-IgA), which has superior sensitivity and specificity. 1

Why Insurance Denies Gliadin Antibody Testing

• Gliadin antibody tests (both IgG and IgA) lack the diagnostic accuracy required for proper celiac disease diagnosis and have been replaced by more reliable tests in clinical practice 2
• Insurance companies follow the most conservative society guidelines, which no longer recommend gliadin antibody testing as a first-line diagnostic tool 3
• The sensitivity of gliadin IgA is only 63% and gliadin IgG is only 42%, compared to tissue transglutaminase IgA at 78% sensitivity and 98% specificity 2
• Medicare and most commercial insurers specifically do not reimburse for gliadin antibody testing because it has been replaced by superior diagnostic methods 1

The Correct Test to Request Instead

For celiac disease screening, order tissue transglutaminase IgA (tTG-IgA) or endomysial antibodies IgA (EMA-IgA), which have insurance coverage and superior diagnostic performance:

• tTG-IgA has 90.7% sensitivity and 87.4% specificity in adults at the 15 U/mL threshold 1
• EMA-IgA has 88.0% sensitivity and 99.6% specificity in adults at the 1:5 threshold 1
• In children, tTG-IgA has 97.7% sensitivity at the 20 U/mL threshold 1
• Deamidated gliadin peptide (DGP) antibodies are superior to traditional gliadin antibodies if gliadin-based testing is specifically needed, with 74% sensitivity and 95% specificity for IgA 2

Strategy If You Must Pursue Gliadin Testing

If there is a specific clinical reason to order gliadin antibodies despite their limitations, follow this approach:

Documentation Requirements

• Write a detailed letter of medical necessity that includes peer-reviewed literature references supporting the clinical validity and utility of the test for your specific patient 1
• Link the test directly to specific symptoms and clinical findings in your documentation, not just screening 4
• Document why standard tTG-IgA or EMA-IgA testing is insufficient for this particular patient 1

ICD-10 Coding Strategy

• Use K90.0 (Celiac disease) if there is prior diagnosis or strong clinical suspicion 4
• Use K90.9 (Intestinal malabsorption, unspecified) for malabsorptive symptoms 4
• Add R19.7 (Diarrhea, unspecified) if present 4
• Include R11.0 (Nausea) or R10.9 (Abdominal pain) as supporting codes 4
• Avoid using Z-codes for screening, as these generally do not justify diagnostic testing in symptomatic patients 4
• Place the most specific diagnostic code first, as some insurance systems only review the primary diagnosis 4

Prior Authorization Approach

• Explicitly state in your prior authorization request why deamidated gliadin peptide antibodies or standard tTG-IgA are inadequate for this clinical scenario 1
• Reference the patient's specific constellation of symptoms that justify the breadth of testing 4
• Include family history of celiac disease or autoimmune conditions as additional supporting evidence 4
• Note any previous positive or equivocal celiac testing that requires further evaluation 4

Critical Pitfalls to Avoid

• Do not order gliadin antibodies as a first-line test when tTG-IgA or EMA-IgA are available and covered 1
• Do not rely on gliadin IgG alone, as it has only 42% sensitivity and 90% specificity 2
• Do not order panels combining IgG, IgA, and IgM gliadin antibodies, as these provide no added benefit and often consist of non-FDA-approved tests 1
• Ensure the patient is not taking proton pump inhibitors, antibiotics, or bismuth for at least 2 weeks before testing, as these can cause false negatives 1
• Remember that gliadin antibodies remain positive long after infection has been treated (serologic "scar"), making them unreliable for monitoring 1

Cost Considerations

• Without insurance coverage, specialized antibody testing can cost thousands of dollars, creating significant financial barriers 3
• Lack of coverage disproportionately affects underserved populations, with uninsured individuals having approximately half the screening rate of insured patients 3
• Consider whether the clinical benefit justifies out-of-pocket costs if insurance denies coverage 3