Lab Test

Hydroxylase Antibody, 21

Test Codes

Mayo: 21OH, EPIC: LAB7121, Beaker: X21HO

Department

Send Outs

Specimen Collection Criteria

Collect (preferred specimen): One plain Red-top tube.

Also acceptable: One Gold-top SST tube.

  • Send specimen for processing immediately after collection.
  • Separate samples must be submitted when multiple tests are ordered.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Transport serum to a plastic transport tube and freeze (-20°C/-4°F or below).

Preparation for Courier Transport

Transport: 1.0 mL serum, frozen (-20°C/-4°F or below). (Minimum: 0.2mL)

Rejection Criteria

Hemolyzed specimens.

Specimens not collected and processed as indicated.

Inpatient Specimen Preparation

Deliver specimen to Laboratory immediately after collection for processing.

In-Lab Processing

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Transport serum to a plastic transport tube and freeze (-20°C/-4°F or below).

Transport: 1.0 mL serum, frozen (-20°C/-4°F or below). (Minimum: 0.2 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable

Refrigerated (2-7°C or 36-46°F): unacceptable

Frozen (-20°C/-4°F or below): 14 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Mayo Clinic Laboratories in Rochester, MN.

Performed

Wednesday.

Results available in 3-10 days.

Reference Range

By report.

Test Methodology

Semi-Quantitative Radioimmunoassay.

Interpretation

The 21-Hydroxylase Antibody assay is intended for the semi-quantitative determination of antibodies to steroid 21-hydroxylase in human serum.

The presence of antibodies to 21-hydroxylase (greater than 1.0 U/mL) is indicative of primary adrenal insufficiency (Addison disease). Results should be interpreted in the context of clinical symptoms including functional adrenal testing.

In males with adrenal insufficiency and 21-hydroxylase antibodies within the reference interval (less than 1.0 U/mL), X-Linked Adrenoleukodystrophy (X-ALD) should be excluded by using Very Long-Chain Branched Fatty Acids in plasma (ARUP Test Code 2004250) for screening.

CPT Codes

83519
LOINC:  17781-6

Contacts

Last Updated

7/1/2021

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