Specimen Requirements

Specimen must be drawn prior to any blood transfusions.

Container/Tube:

Preferred: Green-top (lithium heparin) tube Hemolyzed specimen is not acceptable.

Acceptable: Gold-top serum gel tube, plain red-top tube, or lavender-top (EDTA) plasma

Minimum Specimen Volume: 0.5 mL

Stability: Stable for 2 hours at 15‑25 °C, 48 hours at 2‑8 °C, 56 days at ‑20 °C (± 5 °C). Freeze only once. Stability of serum obtained with separating tubes: 24 hours at 2-8 °C. 

Note: 1. This assay is affected by biotin interference.