Value of basal plasma cortisol assays in the assessment of pituitary-adrenal insufficiency

Clin Endocrinol (Oxf). 1987 Feb;26(2):221-6. doi: 10.1111/j.1365-2265.1987.tb00780.x.


A basal plasma cortisol value taken in a physically unstressed state in 68 patients with or without hypothalamic-pituitary-adrenocortical disease was compared with the maximal plasma cortisol concentration during an insulin tolerance test. There was a strong positive correlation between the values. Basal cortisol levels above 300 nmol/l (RIA method) almost excluded ACTH-cortisol insufficiency and those below 100 nmol/l strongly suggested dysfunction. A repeated basal cortisol estimation within a month was especially valuable in categorizing patients with levels between 100 and 200 nmol/l. We suggest that a basal cortisol measurement may be used as a first laboratory test in patients evaluated for possible hypothalamic-pituitary-adrenocortical insufficiency; in many patients, this approach obviates more sophisticated and expensive testing.

MeSH terms

  • Adolescent
  • Adrenal Insufficiency / blood*
  • Adrenal Insufficiency / diagnosis
  • Adrenal Insufficiency / physiopathology
  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Humans
  • Hydrocortisone / blood*
  • Hypothalamo-Hypophyseal System / physiopathology
  • Insulin
  • Male
  • Middle Aged
  • Pituitary-Adrenal System / physiopathology*
  • Time Factors


  • Insulin
  • Hydrocortisone