Cortisol, Free, Urine
24-hour urine collection required. Refrigerate during collection. Mix well and send 2.0 mL minimum aliquot refrigerated in a screw-capped plastic urine container.
Record total volume on request form and sample label.
Refrigerated 7 days; Frozen 14 days
Assess adrenal function; particularly useful in the diagnosis of Cushing syndrome. Recent data suggest that urinary free cortisol concentrations can be significantly altered in patients taking inhaled corticosteroids