OBJECTIVE: We wished to define the cortisol response to 250 micrograms intramuscular tetracosactrin (Synacthen) in acute hospital admissions, using a modern immunoassay for cortisol. DESIGN: We performed a prospective study of, as near as possible, a consecutive series of 161 admissions to a single unit. PATIENTS: We studied 50 patients (age range 67-98, mean 80.3 years, 31-female, 19-male) admitted as an emergency, from whom it was possible to obtain informed consent, and whom it was possible to study within 24 hours of admission. MEASUREMENTS: We measured baseline, increment and peak serum cortisol following administration of 250 micrograms intramuscular tetracosactrin between 0800 and 0900 hours. RESULTS: Baseline cortisol concentrations ranged from 288 to 1585 nmol/l (mean 706; median 665). Peak cortisol concentrations ranged from 602 to 2265 nmol/l (mean 1076; median 999). Baseline and peak cortisol concentrations showed a significant correlation (P less than 0.001). Increment varied from 10 to 747 nmol/l (mean 374; median 336) and did not correlate with baseline. CONCLUSIONS: In acute hospital admissions, baseline serum cortisol between 0800 and 0900 hours should exceed 250 nmol/l. Peak serum cortisol after 250 micrograms intramuscular tetracosactrin should exceed 600 nmol/l. Calculation of the increment is of no value.
OBJECTIVE: We wished to define the cortisol response to 250 micrograms intramuscular tetracosactrin (Synacthen) in acute hospital admissions, using a modern immunoassay for cortisol. DESIGN: We performed a prospective study of, as near as possible, a consecutive series of 161 admissions to a single unit. PATIENTS: We studied 50 patients (age range 67-98, mean 80.3 years, 31-female, 19-male) admitted as an emergency, from whom it was possible to obtain informed consent, and whom it was possible to study within 24 hours of admission. MEASUREMENTS: We measured baseline, increment and peak serum cortisol following administration of 250 micrograms intramuscular tetracosactrin between 0800 and 0900 hours. RESULTS: Baseline cortisol concentrations ranged from 288 to 1585 nmol/l (mean 706; median 665). Peak cortisol concentrations ranged from 602 to 2265 nmol/l (mean 1076; median 999). Baseline and peak cortisol concentrations showed a significant correlation (P less than 0.001). Increment varied from 10 to 747 nmol/l (mean 374; median 336) and did not correlate with baseline. CONCLUSIONS: In acute hospital admissions, baseline serum cortisol between 0800 and 0900 hours should exceed 250 nmol/l. Peak serum cortisol after 250 micrograms intramuscular tetracosactrin should exceed 600 nmol/l. Calculation of the increment is of no value.