Low agreement between fresh and frozen-thawed platelet-rich plasma in the calibrated automated thrombogram assay

Introduction: Thrombin generation tests (TGTs) are considered to give more detailed information of the overall coagulation capability of a patient than clotting-based routine assays. The TGT thrombin generation assay-calibrated automated thrombogram (TGA-CAT) uses both platelet-poor plasma (PPP) and platelet-rich plasma (PRP). Assessing PRP gives more physiological test conditions and is of great interest considering the important role platelets play in haemostasis. However, PRP needs to be assessed close after blood draw/preparation as freezing fragments the platelets. In several previous publications, the utility of frozen-thawed PRP (ft-PRP) has been promoted, and in one article, no significant difference between fresh PRP (f-PRP) and ft-PRP was reported. Aim: The aim of our study was to investigate the level of agreement between f-PRP and ft-PRP to further validate these results. Methods: Our test population contained 41 persons with haemophilia and 45 healthy subjects. We used the TGA-CAT method with a set-up according to the manufacturer of the method. Results: The measurements showed a poor level of agreement between f-PRP and ft-PRP and differences were not systematic. Conclusion: Fresh and ft-PRP cannot be assumed to show equal results in the TGA-CAT assay.