Separate serum from the blood within 60 minutes of venipuncture. Recommended guidelines for optimal sample processing should be followed. Specimen must be free of particulate matter including fibrin. Specimens transported to Marshfield must be removed from the primary collection tube and sent in a labeled daughter tube. Store samples at 2 to 8°C if not tested within 8 hours of collection. The frozen specimens should be completely thawed thoroughly mixed and centrifuged before analysis. 4 freeze/thaw cycles has shown to have no qualitative difference in results.
High doses of exogenous biotin (also termed Vitamin B7, Vitamin H or Coenzyme R) may interfere with this assay (A-M, A). It is recommended that patients refrain from consuming any multivitamin or supplement containing biotin for at least 72 hours prior to collection of a blood sample.