Effects of conserving plasma pools on coagulation exploration tests

Abstract

Introduction: Coagulation exploration tests are part of the most commonly performed hemobiologic practice in the hematology laboratory of the Joseph Ravoahangy Andrianavalona University Hospital Center (JRA UHC) Antananarivo. As an internal quality control, it uses commercial reference plasmas. These are expensive with minimal shelf life. This study aims to identify the preservation method that allows more extended stability of coagulation proteins.

Methods: This is a study spanning a period of 31 days, ranging from October 02^nd to November 03^rd, 2018. A series of two tests: prothrombin time (PT) and Partial thromboplastin time (APTT), was performed on normal and pathological plasmas stored in 3 different ways: refrigeration at 8-10 ° C, freezing at -20 °C and thawing in a water bath at 37 °C for 5 minutes and freezing at -20 °C and then thawing at room temperature 20-24 °C.

Results: Over the 31 days, PT and APTT median values from the normal plasma pool according to the conservation methods are: 29.4 s, 14.3 s, 15.3 s and 66.9 s, 35.8 s, and 36.8 s. And those from the pathological plasma pool according to the methods of preservation are 37.9 s, 17.2 s, 17.2 s and 88s, 40.1s, and 40s. Freezing methods stabilize coagulation proteins more than the refrigeration method. Thawing in a water bath is better than that at room temperature to stabilize the pool of plasmas.

Conclusion: Method number two, freezing at -20 °C and then thawing in a water bath at 37 °C for 5 minutes before testing, is the most effective for maintaining stable plasma.