Draw blood in a plain red-top tube(s) or serum gel tube(s). Separate serum from cells within 1 hour and send 2 tubes of serum, 2.5 mL in first tube and 0.5 mL in second tube frozen in plastic screw-capped tubes. Ship frozen. SPECIMEN STABILITY INFORMATION: Specimen Type Temperature Time Serum Frozen (preferred) Refrigerated 72 hours.