0.5 mL serum in red top or serum separator tube for baseline sample (labeled PRE) and 0.5 serum in red top or serum separator tube for each post sample (labeled POST).
Test Description
Cortisol Assay, 3 Samples: PRE (Baseline) and 2 POST Dexamethasone Suppression.
This test measures cortisol concentrations before and after administration of exogenous dexamethasone. This suppression test requires three samples; baseline cortisol prior to dexamethasone administration and two cortisol levels post dexamethasone administration (4 and 8-hours). The low‑dose dexamethasone suppression test is preferred for diagnosing hyperadrenocorticism. The high‑dose dexamethasone suppression test is used to differentiate pituitary‑dependent from adrenal tumor hyperadrenocorticism.
Interferences: Marked hemolysis may affect results, and marked lipemia (if unable to be cleared by centrifugation) may falsely decrease cortisol levels.