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Laboratory Tests 

The goals with congenital adrenal hyperplasia (CAH) testing are to:

  • Screen all newborns for 21-hydroxylase deficiency
  • Help confirm the condition in those with positive newborn screens
  • Help diagnose the condition in those with symptoms
  • Identify the carrier status of a person who has a family member with 21-hydroxylase deficiency
  • Determine the chromosomal sex (XX or XY) of a newborn with genitals that are not clearly male or female (ambiguous genitalia)
  • Monitor treatment for CAH and detect overtreatment
  • Evaluate and monitor the health status of a person with an adrenal crisis
  • Detect 21-hydroxylase deficiency during pregnancy (sometimes)
  • Identify and/or rule out other types of CAH besides 21-hydroxylase deficiency (sometimes)

Testing may include:



  • 17-OHP – concentrations may be greatly elevated with 21-hydroxylase deficiency
  • Steroid profile on a spot urine specimen – this looks at the pattern of steroids in a urine specimen, and is a very sensitive method for detecting abnormal steroid production
  • ACTH stimulation – measures the level of cortisol in a person's blood before and after an injection of synthetic ACTH (Synacthen™). If the adrenal glands are functional, cortisol concentrations will rise in response to the ACTH stimulation; not performed frequently
  • Additional testing may be performed when 17-OHP is elevated,, depending upon which deficiencies and accumulations of precursors are suspected; may include several of the following:
  • Aldosterone and renin – to determine if concentrations of these substances are normal
  • Chromosome studies – to determine a baby's sex by evaluating their chromosomes (XX (female) or XY (male))
  • Genetic testing – performed to detect gene mutations; not usually needed for diagnosis but may be used for prenatal diagnosis of 21-hydroxylase deficiency and for detecting gene mutation(s) in family members to help determine carrier status; will detect the most common mutations. If a specific mutation has been identified in a family, testing should include that mutation.
Monitor treatment, every few months:
  • 17-OHP in a blood spot or saliva specimen
  • Androstenedione
  • Testosterone

Health status, during illness, and to monitor:

Non-Laboratory Tests

  • Blood pressure
  • Pelvic ultrasonography to evaluate internal reproductive organs in females
  • Hand X-ray or bone-age study to evaluate rate of skeletal growth

Last Review Date: January 19, 2017