Centrifuge and aliquot serum into plastic vial to remove from cells or gel prior to shipping.
Ship serum specimen frozen
Lipemic or grossly hemolyzed serum should not be used in this assay.
Results should be interpreted in the context of clinical symptoms and adrenal functional confirmatory tests.
Addison disease is the most frequent cause of primary adrenal insufficiency.
Auto-antibodies against 21-hydroxylase are present in up to 90% of Addison disease cases.
Measurement of anti-21-hydroxylase auto-antibodies is useful in the evaluation of the cause of established primary adrenal insufficiency.
This is a qualitative test. A positive result indicates the presence of autoantibodies to 21-hydroxylase and is consistent with Addison disease.
Utilizing an index value of <45 as a negative cutoff, this assay has a clinical sensitivity and specificity of 87.0% (95% CI: 79.4%-92.2%) and 99.3% (95% CI: 97.5%-99.8%), respectively.