Determining the optimal storage time and temperature for performing platelet function assays and global hemostasis assays.

Platelet function assays and global haemostasis assays are essential in diagnosing bleeding tendencies, with light transmission aggregometry (LTA) as golden standard. The Multiple Electrode Aggregation (Multiplate), platelet function assay (PFA) and rotational thromboelastometry (ROTEM) are mostly used as whole-blood screening tests. Currently, patients have to travel to specialized laboratories to undergo these tests, since specific expertise is required. Pre-analytical variables, like storage time and temperature during transport, are still considered to be the most vulnerable part of the process and may lead to discrepancies in the test results. We aim to give a first impression on the stability of blood samples from healthy volunteers during storage and investigate the effect of storage time (1, 3, 6 and 24 hours) and temperature (4°C, room temperature and 37°C) on the Multiplate, PFA, ROTEM and LTA test results. Our data indicated that, for the PFA, whole blood can be stored for 3 hours at room temperature. Whole blood used for the Multiplate and ROTEM can be stored for 6 hours of storage. For LTA, PRP and whole blood were stable up to 3 hours at 4°C or room temperature and 6 hours at room temperature, respectively.

Determining the maximal storage time of centrifuged citrated samples for performing add-on routine coagulation tests.

BACKGROUND: Several routine coagulation tests have been developed to give insight in the coagulation pathway. The laboratory diagnostical process consists of 3 phases, the pre-analytical, analytical and post-analytical phase; however, the pre-analytical phase is most sensitive to errors. The amount of time blood is stored, can affect the measurements of these coagulation tests and result in an incorrect conclusion. Therefore, we performed experiments to determine the maximal storage time, centrifuged blood samples can be reliably measured. METHODS: Citrated whole blood from hospital patients, who were tested for routine coagulation, was collected in 2.7 mL citrate tubes. These whole blood samples were centrifuged and the plasma was stored on top of the cell pellet at room temperature. After 2 h, 4 h, 6 h, 12 h and 24 h, the prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen concentration, antithrombin activity, D-dimer concentration and thrombin time were measured using Sysmex CS2100 coagulation analysers. RESULTS AND CONCLUSION: Analytical evaluation of routine coagulation tests resulted in various significant differences and large variations between the various time intervals. Our results indicated that the PT and INR can be measured up till 24 h of storage. Centrifuged blood for measuring the fibrinogen concentration, antithrombin activity, D-dimer concentration and thrombin time can be stored up to 4 h, while 2 h of storage might already be too long for obtaining reliable aPTT measurements.