21-Deoxycortisol, Serum
Use
The test is useful as an adjunct to the measurement of 17-hydroxyprogesterone, androstenedione, and cortisol in diagnosing suspected 21-hydroxylase (CYP21A2) deficiency. It also aids in identifying heterozygote CYP21A2 deficiency carriers and in following up with children with the deficiency, contributing to evaluating treatment effectiveness for congenital adrenal hyperplasia (CAH). Measurement of 21-deoxycortisol can confirm 17-hydroxyprogesterone and androstenedione data in difficult CAH cases attributed to CYP21A2 deficiency.
Special Instructions
Collection should be performed in the morning at around 8 a.m. A red top tube is preferred for collection, with serum needing to be centrifuged and aliquoted into a plastic vial.
Limitations
The test has limitations in discriminating CAH forms that involve 11-hydroxylase deficiencies. Caution is required when interpreting results, especially in newborns where repeat testing might be necessary due to elevated hormone levels from stress or illness. Additionally, 21-deoxycortisol levels can be less reliable when pubertal changes in sex steroid production occur, thus requiring careful interpretation and support from other markers.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 74872-3
- 74872-3
Result Turnaround Time
3-10 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
0.5 mL
Minimum Volume
0.4 mL
Container
Plastic vial
Collection Instructions
Morning (8 a.m.) specimen preferred. Centrifuge and aliquot serum into a plastic vial.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 21 days |
| Frozen | 21 days |