Problems by using whole blood in heparin measurements.
Problems by using whole blood (WB) of various packed cell volume (PCV) in heparin measurements were studied. WB had to be used within 1 hr, due to influence of platelet Factor 4. The increase of Ca++ by increasing PCV, had a moderate influence by the assays studied. The recalcification time (RT) of WG was time-consuming and had low accuracy and precision, due to different heparin response. The activated partial thromboplastin time (APTT) also had low accuracy and precision, due to different heparin response; the results were equal for WB and plasma. The thrombin clotting time (TCT) had high accuracy and precision in plasma. The TCT could also be used for WB since there was a good correlation between T20 (20 NIH U thrombin/ml) using WB, and T30 using plasma (r = 0.89, N = 61). The calcium thrombin clotting time (CaTCT) is not recommended for WB assaying.
D001800:Blood Specimen Collection; D002118:Calcium / Q000494:pharmacology; D006400:Hematocrit; D006493:Heparin / Q000097:blood*; D006801:Humans; D010314:Partial Thromboplastin Time; D010949:Plasma
D006493:Heparin; D002118:Calcium