Effect of multiple time point sampling on the sensitivity of the dexamethasone suppression test

Dexamethasone suppression test sensitivity in 188 patients was 61.6% when cortisol was measured at six time points and 48.5% when cortisol was measured twice. More patients had abnormal cortisol levels at 8:00 p.m. than at 4:00 p.m. or 10:00 p.m.