Specimen Requirements

Preferred Collection Container: green top lithium heparin tube, SST 

Also Acceptable Collection Container: serum red top tube or EDTA purple top tube 

Collection Information:

1 mg dose of oral dexamethasone is given at 23:00 and cortisol levels are drawn at 08:00, 16:00, and an optional 23:00 the following day.

Collect 1 mL of Lithium heparinized plasma or serum at each collection time.

Serum or plasma must be separated from cells within 2 hours of collection.