cortisol in serum

Reference interval

• 10-25 ug/dL, 8 AM (normal AM cortisol)
  • 5-25 ug/dL (138-690 nmol/L)
• 5-12 ug/dL, 10 PM
  • diurnal variation; AM > PM cortisol
  • serum level at 10 PM is generally 50% of that at 8 AM
• acute stress: 20-120 ug/dL
• random cortisol of > 18-20 ug/dL makes adrenal insufficiency unlikely

Increases

• hypoglycemia
• stress
• ether narcosis
• pregnancy
• obesity
• depression
• hyperthyroidism
• Cushing' syndrome

Decreases

• hypothyroidism
• cirrhosis
• hepatitis
• adrenal insufficiency

Methods

• Radioimmunoassay (RIA)
• other competitive binding assays with fluorescent detection

Interferences

• in vivo
  • agents that increase serum cortisol levels
    • amphetamines, corticotropins, cortisone acetate, estrogens, ethanol, hydrocortisone, interferon gamma, methoxamine, metoclopramide, naloxone, nicotine, oral contraceptives, vasopressin
  • agents that decreased serum cortisol levels
    • aminoglutethimide, beclomethasone, betamethasone, danazol, desoximetasone, dexamethasone, etomidate, ketoconazole, levodopa, lithium carbonate, methylprednisolone (depot), metyrapone, morphine, phenytoin (women), trilostane
• chemical interferences
  • RIA: estrogen, prednisolone, prednisone
  • fluorescence: mepacrine, quinacrine, spironolactone
  • other increases: chlordiazepoxide, dexamethsone, digoxin, methenamine, thorazine

Notes

• serum levels are influenced by clearance rates, thus serum levels may be normal when cortisol secretion is increased or decreased

* Most serum cortisol is bound to corticosteroid-binding globulin & albumin. Thus free cortisol is the physiologically active form. Diminished total, but not free cortisol may be a result of diminished serum albumin.

Cortisol secretion is not influenced by age.

More general terms

• cortisol in body fluid

More specific terms

• cortisol in serum at specified time
• cortisol in serum baseline
• cortisol in serum post ACTH

Component of

• intravenous salt loading test
• fludrocortisone suppression test
• anterior pituitary evaluation panel
• testosterone/cortisol in serum/plasma
• 11-deoxycortisol/cortisol in serum
• dehydroepiandrosterone sulfate (DHEA-S)/cortisol in serum/plasma

Patient information

cortisol in serum patient information