Specimen Requirements

Specimen Type: Plasma or Serum drawn 3-5 PM

Container/Tube:

Plasma: Lithium heparin, sodium heparin or potassium EDTA

Serum: Clot, plain, activator, or gel separator

Specimen Volume: 1 mL

Specimen Minimum Volume: 0.3 mL

Collection Instructions: Separate serum from cells as soon as possible after collection.

Additional Information:

 Patients receiving Prednisolone or Prednisone (which is converted to Prednisolone in vivo) therapy may be falsely elevated. Caution must be exercised with cortisol determinations for patients undergoing therapy with these and structurally related synthetic corticosteroids. Heterophilic antibodies can react with reagent immunoglobulins, interfering with in vitro immunoassays.