Effect of Delayed Preparation of Platelet Poor Plasma on Coagulation Studies at Room Temperature

Abstract

Objective: To determine the effect of delay in the preparation of platelet poor plasma (PPP) on prothrombin time (PT) and activated partial thromboplastin time (APTT) at room temperature (RT). Material and Methods: It was a cross sectional study, conducted at Chughtai Institute of Pathology from January 2022 to June 2022. Total 100 healthy individuals, both males and females, participated in the study. Centrifugation of four citrated blood samples was done at 4000 g for 10 minutes at RT; first sample at 0 hour (h), second sample at 4 h, third sample at 8 h and fourth sample at 24 h. PT and APTT were run on each PPP using Sysmex CS-1600.The values at different times were noted and compared through careful statistical analysis of the observed parameters. Results: There was statistically significant difference for PT at 24h storage time when compared with baseline value at 0h (P value 0.0017) but no clinically relevant change up to 24h (<10% percent change). For APTT at RT, statistically significant difference was noted at storage time of 8h (P value 0.0001) and 24h (P value <0.0001) but a clinically relevant change was noted only at 24h (>10% percent change). Conclusion: Blood samples for PT and APTT without centrifugation can be stored for up to 24 hours for PT at RT and for up to 4 hours for APTT at RT. PT and APTT values will not be affected if centrifugation of citrated sample is done within 1 hour of collection and transported at RT in small aliquots. Key Words: Prothrombin time, Activated partial thromboplastin time, Platelet poor plasma, Pre analytical, Centrifugation