Serum (RTT or SST): Samples collected in a RTT must be removed from the clot within one hour for storage or transport. Samples collected in a SST must be processed and serum removed from the primary tube within 4 hours for storage or transport.
Citrated Plasma (BTT):
- Collect in Citrated Blue Top Tube (BTT)
- Citrate anticoagulant must be adjusted for HCT >55%.
- Tube must be at least 90% full.
- Invert completely 3-4 times (without shaking) to mix.