Alternatives for Measuring Endogenous Adrenocortical Activity in Asthmatics Treated with Inhaled Corticosteroids.

We compared a 12-hour, hourly integrated plasma cortisol profile in asthmatics treated with a corticosteroids with a variety of modified methods based on less frequent blood sampling. Excellent agreement with the reference was observed for sampling at 10 p.m. and 8 a.m. (correlation coefficient of 0.97; 95% confidence interval 0.97, 0.98); at 9 p.m. and 7 a.m. ( r = 0.95; 0.94, 0.96); at 11 p.m. and 7 a.m. (r = 0.94; 0.93, 0.95); every 2 hours (r = 0.96; 0.96, 0.97); and every 3 hours (r = 0.91, 0.91, 0.93). The two-sample alternatives (10 p.m/8 a.m. and 9 p.m/7 a.m.) are accurate, as well as more convenient, economical, and practical. [ABSTRACT FROM AUTHOR]