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HelpEpic Code LAB1230584 21-Hydroxylase Antibodies, Serum
Additional Codes
Mayo Code: 21OH
Interface Code: 1230584
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Investigating adrenal insufficiency
Aiding in the detection of those at risk of developing autoimmune adrenal failure in the future
Specimen Type
SerumOrdering Guidance
Testing for auto-antibodies against 21-hydroxylase is recommended following confirmation of adrenal insufficiency to help differentiate between causes of primary adrenal insufficiency
Shipping Instructions
Ship serum specimen frozen
Specimen Required
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial to remove from cells or gel prior to shipping.
COLLECTION NOTE: Volumes listed are in serum or plasma, draw approximately 2 1/2 times the requested volume in whole blood.
Specimen Minimum Volume
0.2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen | 14 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Day(s) Performed
Tuesday
Reference Values
Negative
Clinical Information
Adrenal insufficiency is caused by failure of the adrenal cortex to produce cortisol. This failure can result from loss of function of the adrenal glands (ie, primary adrenal insufficiency). This is most frequently caused by autoimmune adrenalitis or Addison disease accounting for 68% to 94% of cases. It can occur sporadically or in combination with other autoimmune endocrine diseases that together comprise type I or II autoimmune polyglandular syndrome (APS).
Antibodies that react with several steroidogenic enzymes (most often 21-hydroxylase) are present in the serum of up to 86% of patients with autoimmune primary adrenal insufficiency but only rarely in patients with other causes of adrenal insufficiency. Therefore, anti-21-hydroxylase autoantibodies (21-OH Abs) are markers of autoimmune Addison disease, whether it's present alone or as part of type I or II APS. The measurement of 21-OH Abs is an important step in the investigation of adrenal insufficiency and may aid in the detection of those at risk of developing autoimmune adrenal failure in the future.
Cautions
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.
In rare cases, some individuals can develop antibodies to mouse or other animal antibodies (often referred to as human anti-mouse antibodies [HAMA] or heterophile antibodies), which may cause interference in some immunoassays. Caution should be used in interpretation of results and the laboratory should be alerted if the result does not correlate with the clinical presentation.
Interpretation
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.
Reporting Name
21-Hydroxylase Ab, SMethod Name
Enzyme-linked Immunosorbent Assay (ELISA)
Method Description
A reference preparation, controls, and patient specimens are incubated with a reaction enhancer overnight in a coated enzyme-linked immunosorbent assay (ELISA) plate. 21-Hydroxylase (21-OH) antibodies (Ab) act divalently and form a bridge between 21-OH Ab coated on ELISA plate wells and liquid phase 21-OH biotin. The resulting antigen-antibody-antigen complexes are then detected by the addition of streptavidin peroxidase and tetramethylbenzidine to produce a colorogenic reaction. Stop solution is added to halt the reaction, and absorbance is read using an ELISA plate reader. The absorbance of each well is directly proportional to the amount of antibody present. Positive and negative determinations are based on index values. Index values are calculated from the mean value of duplicate sample wells and compared to a reference value.(Package insert: 21-Hydroxylase Autoantibody (21-OHAb) ELISA Kit, Kronus; 01/2019)
CPT Code Information
83516
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| 21OH | 21-Hydroxylase Ab, S | 85363-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 607788 | 21-Hydroxylase Ab, S | 85363-0 |
Report Available
3 to 9 daysTest Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.Clinical Reference
1. Charmandari E, Nicolaides NC, Chrousos GP: Adrenal insufficiency. Lancet. 2014 Jun 21;383(9935):2152-2167
2. Bancos I, Hahner S, Tomlinson J, Arlt W: Diagnosis and management of adrenal insufficiency. Lancet Diabetes Endocrinol. 2015 Mar;3(3):216-226
3. Bornstein SR, Allolio B, Arlt W, et al: Diagnosis and treatment of primary adrenal insufficiency: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2016 Feb;101(2):364-389
Highlights
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.