BTT (blue top tube with sodium citrate anticoagulant).
Volume
300uL per test preferred; Call (530) 759-8533 for lesser volume.
Handling
Gently mix samples immediately after filling. Allow to sit for at least 5 minutes. Centrifuge sample for 15 minutes @ 3000rpm. Transfer plasma to plastic tube and label as citrated plasma. Sample should be frozen if testing is not done immediately.