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21-Deoxycortisol, 24-Hour Urine — Mass Concentration

Published: August 9, 2026Updated: August 16, 2026

A specialized steroid test that measures 21-deoxycortisol in urine collected for 24 hours to help evaluate adrenal hormone production.

Quick summary

["This test can help identify disorders that affect cortisol production, but an incomplete urine collection or certain medicines may affect the result."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
57633-0
Short code
A-cortolone Pre Dex 24h Ur-mCnc
Synonyms
A-cortolone Pre Dex 24h Ur-mCnc
Category
liver
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What is this test?

21-deoxycortisol is a precursor in the pathway that produces cortisol. This test measures its concentration in a 24-hour urine collection and may be used to evaluate adrenal steroid production.

Why might I need this test?

This test may be ordered when a clinician is evaluating possible congenital adrenal hyperplasia, a group of inherited conditions that affect adrenal hormone production. It may also be used in the assessment of unusual adrenal steroid levels.

How is the test performed?

Urine is collected into a labeled container for a full 24-hour period, usually beginning with an empty bladder. The total volume and collection times are recorded, and the laboratory measures the amount of 21-deoxycortisol in the urine.

How do I prepare for the test?

Follow the collection instructions provided by the laboratory and collect all urine for exactly 24 hours. Tell your clinician about steroid medicines or other medicines you are taking, because they can affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated result may indicate reduced activity of an enzyme involved in cortisol production, such as 21-hydroxylase deficiency, although it must be interpreted with other adrenal hormone tests. Results can also be affected by medications, temporary changes in adrenal function, or an incomplete urine collection, so abnormal results should be reviewed by a clinician.

Short name

21-Deoxycortisol, 24-Hour Urine

Frequently asked questions

Do I need to fast for this test?
Fasting is generally not required for a 24-hour urine collection. Follow any specific instructions from your clinician or laboratory.
What happens if the urine collection is incomplete?
An incomplete or mistimed collection can make the result unreliable. The laboratory or clinician may ask you to repeat the test using a full 24-hour collection.
Can medicines affect the result?
Yes. Corticosteroids and other medicines that influence adrenal hormone production may change 21-deoxycortisol levels. Do not stop or change medicines without medical guidance.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy