Congenital Adrenal Hyperplasia - CAH

Last Literature Review: May 2018 Last Update:

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders caused by several distinct enzymatic defects that result in changes in steroidogenesis. These disruptions cause irregular genital and sexual characteristics, and interfere with electrolyte balance. Newborn screening detects elevations in 17-hydroxyprogesterone (17-OHP). Other forms of CAH without significant 17-OHP increases are often not identified until later in life due to their more subtle clinical presentations. Initial testing generally involves 17-OHP testing and, if 17-OHP is increased, adrenocorticotropic hormone (ACTH) testing.


Indications for Testing

  • Ambiguous genitalia or unexplainable electrolyte results in infancy
  • Premature sexual development in older children
  • Hirsutism and irregular menses in adult females

Laboratory Testing

  • Initial testing
    • 17-OHP
      • If elevated, perform ACTH stimulation (cosyntropin)
        • Often unnecessary when there is marked elevation of 17-OHP
        • 17-OHP remains increased after stimulation in classic CAH
      • If nonclassic form is suspected in adult female, obtain 17-OHP at 0800 hours and during follicular phase of menstrual cycle
      • Further evaluation should include assessment of salt wasting
        • Serum sodium, potassium, and renin activity: expect hyponatremia, hyperkalemia, and increased renin in classic 21-hydroxylase deficiency CAH
  • Secondary testing
    • Adrenal steroid quantitative panel: if ACTH stimulation is abnormal or if a marked elevation of 17-OHP is noted
      • 21-hydroxylase deficiency
        • Characterized by markedly elevated plasma 17-OHP
      • 11-beta-hydroxylase deficiency
        • Indicated by increased 11-deoxycorticosterone and 11-deoxycortisol levels
      • 17-hydroxylase (17-OH) deficiency
        • Characterized by increased pregnenolone, 11-deoxycorticosterone, and corticosterone, and decreased 17-hydroxypregnenolone (17-OH-pregnenolone)
      • 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) deficiency
        • Indicated by increased pregnenolone, 17-OH pregnenolone, dehydroepiandrosterone (DHEA), and DHEA sulfate (DHEAS)
  • Testing in infants
    • Karyotyping to rule out chromosomal disorder
    • Pelvic ultrasonography to assess internal genital organs in females
    • Assess glucose, electrolytes, liver function, and blood gases in infants suspected of acute adrenal insufficiency


  • Newborn screening for CAH in most states: 17-OHP
    • Threshold for positive tests is set relatively low to prevent missing true positives
    • False positives common in premature infants, who tend to have increased 17-OHP
      • Markedly increased 17-OHP confirms disease
        • Follow up positive results with ACTH stimulation in all infants
    • False negative may occur if maternal glucocorticoids are administered
  • Prenatal diagnosis
    • Chorionic villus sampling or amniocentesis, 90-95% sensitive
    • Allows for prenatal treatment of disease through administration of maternal glucocorticoid​


  • For assessment of glucocorticoid replacement
    • 17-OHP, androstenedione, and testosterone
      • Every 3 months during infancy and every 3-6 months thereafter
  • For assessment of mineralocorticoid replacement
    • Blood pressure measurement
    • Plasma renin/renin activity
    • Aldosterone and potassium levels may also be helpful

ARUP Laboratory Tests

Primary Tests

Components include androstenedione; 17-OHP; 17-hydroxypregnenolone, quantitative by LC-MS/MS; and dehydroepiandrosterone​

Components include androstenedione; 17-OHP; testosterone; 11-deoxycortisol, quantitative by LC/MS-MS; and dehydroepiandrosterone

Components include 11-deoxycortisol, quantitative; 17-OHP, quantitative by MS/MS; 17-hydroxypregnenolone, quantitative by MS/MS; and pregnenolone by MS/MS

Components include androstenedione; 17-OHP, quantitative by LC-MS/MS; and testosterone, females or children

Related Tests

Panel includes albumin; alkaline phosphatase; aspartate aminotransferase; alanine aminotransferase; bilirubin, direct; protein, total; and bilirubin, total


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