free cortisol in 24 hour urine
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Indications
- evaluation of Cushing's syndrome
- evaluation of Addison's disease
Contraindications
- not sufficiently sensitive to assess for cortisol excess in the setting of adrenalomas[6]
- not accurate during acute illness[6]
Reference interval
- adults: 20-90 ug/day (55-248 nmol/day)
- children 11-20 years of age: 5-55 ug/day (14-152 nmol/day)
- children 1-10 years of age: 2-27 ug/day (6-74 nmol/day)
Increases
- pharmaceutical agents
- clinical disorders
- Cushing's syndrome, late pregnancy, stress
Decreases
- pharmaceutical agents
- clinical disorders
Methods
Specimen
- preserve with 1 g boric acid to maintain pH < 7.5
- freeze -20 C for long-term storage
Notes
- normal cortisol variations & pulsatile nature of secretion makes random specimens of limited use
- 24 hour urine creatinine should be collected simultaneously to assess completeness of urine collection
- renal insufficiency can impair cortisol excretion
More general terms
Additional terms
Component of
References
- ↑ Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
- ↑ 2.0 2.1 Medical Knowledge Self Assessment Program (MKSAP) 11, 17 American College of Physicians, Philadelphia 1998, 2015
- ↑ Clinical Chemistry, Principles, Procedures, Correlations, 2nd ed., Bishop, Duben-Engelkirk, Fody (eds), JB Lippincott, Philadelphia, 1991, pg 1826
- ↑ Medline Plus: Cortisol - urine http://www.nlm.nih.gov/medlineplus/ency/article/003703.htm
- ↑ Panel of 12 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0092100.jsp
Panel of 8 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0097222.jsp - ↑ 6.0 6.1 6.2 NEJM Knowledge+ Question of the Week. May 29, 2018 https://knowledgeplus.nejm.org/question-of-week/1833/