:Normal range
6-57 pg/ml 1.3-12.5 pmol/L
Comment: Useful, along with cortisol, in the differentiation between primary and secondary adrenal insufficiency (high in primary, and low in secondary). In pituitary-dependent Cushing’s syndrome ACTH is elevated with loss of diurnal cortisol rhythm. Very high values are found in Cushing’s syndrome caused by an ectopic ACTH-secreting or corticotrophin –releasing tumor, and Addison’s disease. Low values with loss of diurnal variation occur in Cushing’s syndrome caused by an adenoma or carcinoma
Sample: EDTA, plasma, under ice