21-Hydroxylase Autoantibodies, Serum
Also known as: 21OH AB
Use
The 21-Hydroxylase Autoantibody assay is a qualitative test used to determine the presence of autoantibodies to steroid 21-hydroxylase in human serum. A positive result indicates the presence of primary adrenal insufficiency, commonly known as Addison's disease. This autoimmune condition affects the adrenal glands' ability to produce essential hormones, compromising vital body functions. It is crucial to interpret results within the context of clinical symptoms and possible adrenal functional testing. Particularly, males showing adrenal insufficiency and negative for 21-hydroxylase autoantibodies should consider screening for X-Linked Adrenoleukodystrophy (X-ALD) with a specialized test for Very Long-Chain Branched Fatty Acids.
Special Instructions
The test is a secondary diagnostic tool used after confirmation of adrenal insufficiency. For effective test results, it is important to transfer serum samples to a standard transport tube accurately and maintain appropriate storage conditions.
Limitations
The assay is qualitative and is designed specifically to identify autoantibodies against steroid 21-hydroxylase. Analytical interpretation must occur alongside clinical symptom evaluation. False negatives can occur, particularly in patients with other adrenal-related conditions. It's not suitable for exclusive use without consideration of comprehensive clinical findings.
FDA ApprovedNew York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 85363-0
Result Turnaround Time
2-7 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.3 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Transfer the serum from Serum Separator Tube (SST) or Plain Red to transport tube.
Storage Instructions
Refrigerated transport required.
Causes for Rejection
Grossly hemolyzed or lipemic specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 1 week |
| Frozen | 1 month |