Prospective evaluation of a week one overnight metyrapone test with subsequent dynamic assessments of hypothalamic-pituitary-adrenal axis function after pituitary surgery.

Overnight metyrapone test within the first week after pituitary surgery was no better than an early morning cortisol level at predicting glucocorticoid requirement at 6 months. OMT at week 6 demonstrated recovery of HPA axis in a substantial proportion of participants who failed earlier assessments; thus, definitive testing should be delayed until 6 weeks post-operatively.