Evidence check: Insulin in the context of skin aging

Whether a DNA test (e.g., for HLA types) can tell you if you have gluten sensitivity or celiac disease requires careful nuance. For celiac disease, testing for HLA-DQ2 and HLA-DQ8 is well-established: absence of these variants virtually rules out celiac (negative predictive value >99%). However, a positive result does not diagnose celiac, as ~30% of the general population carry these risk alleles but only a minority develop the disease. Definitive diagnosis requires serology (tTG-IgA) and duodenal biopsy. For non-celiac gluten sensitivity (NCGS), no validated genetic marker exists; diagnosis is based on exclusion and challenge. MyBody-X's HLA test can serve as a rule-out tool but cannot replace clinical workup. Evidence for the HLA-celiac link is human-strong, but clinical utility is limited to risk assessment. IgG food panel tests are not recommended by medical guidelines. Caution: a positive HLA result alone does not justify a gluten-free diet without physician confirmation.