Internal: Deliver to lab immediately.
Offsite: Allow to clot for 30 minutes, centrifuge within 2 hours of collection, then transport to lab refrigerated/on ice (2-8 degrees C).
Before centrifugation: 2 hours.
After centrifugation: Ambient, 8 hours; Refrigerated, 48 hours; Frozen, 7 days
Serum aliquot: Ambient, 8 hours; Refrigerated, 48 hours; Frozen, 7 days