Effect of freezing plasma at -20°C for 2 weeks on prothrombin time, activated partial thromboplastin time, dilute Russell viper venom time, activated protein C resistance, and D-dimer levels.

To assess the impact of preanalytical variables of time and temperature on prothrombin time (PT), activated partial thromboplastin time (aPTT), dilute Russell viper venom time (DRVVT), activated protein C resistance (APCR), and d-dimer, samples from 23 healthy individuals and 18 patients having coagulopathy with known abnormal PT and aPTT were collected. Plasma from each individual was separately pooled and aliquoted; the first 2 aliquots were stored at room temperature then analyzed at 2 hours (baseline) and 4 hours postcollection. The remaining aliquots were stored at -20°C and thawed for analysis at 48 hours, 1, and 2 weeks. In both healthy participants and participants with coagulopathy, PT, aPTT, APCR, DRVVT, and D-dimer had no significant changes at 4 and 48 hours, and 1 and 2 weeks postcollection compared to baseline, or the changes were less than 10%. The results indicate PT, aPTT, DRVVT, APCR, and d-dimer can be stored for 2 weeks at -20°C without compromising clinical interpretation in both healthy individuals and individuals with coagulopathy. Increasing storage time will facilitate sample processing from off-site clinics.

Foshat M ，Bates S ，Russo W ，Huerta A ，Albright K ，Giddings K ，Indrikovs A ，Qian YW ... -  《-》

Is it acceptable to use coagulation plasma samples stored at room temperature and 4°C for 24 hours for additional prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin, and D-dimer testing?

Coagulation laboratories are faced on daily basis with requests for additional testing in already analyzed fresh plasma samples. This prompted us to examine whether plasma samples stored at room temperature (RT), and 4°C for 24 hours can be accepted for additional prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen (Fbg), antithrombin (AT), and D-dimer testing. We measured PT, aPTT, Fbg in 50 and AT in 30 plasma samples with normal and pathological values, within 4 hours of blood collection (baseline results) and after 24-hours storage at RT (primary tubes), and 4°C (aliquots). D-dimer stability was investigated in 20 samples stored in primary tubes at 4°C. No statistically significant difference between baseline results and results in samples stored at RT and 4°C was observed for PT (P=.938), aPTT (P=.186), Fbg (P=.962), AT (P=.713), and D-dimers (P=.169). The highest median percentage changes were found for aPTT, being more pronounced for samples stored at 4°C (13.0%) than at RT (8.7%). Plasma samples stored both at RT and 4°C for 24 hours are acceptable for additional PT, Fbg, and AT testing. Plasma samples stored 24 hours in primary tubes at 4°C are suitable for D-dimer testing.

Rimac V ，Coen Herak D 《-》

Effect of Pre-analytical Conditions on Prothrombin Time and Partial Activated Thromboplastin Time.

Clinical analysis often involves clotting assays. Although the guidelines suggest the storing and freezing of samples before these assays, there are contradictory results in the literature. The objective of this study was to analyse the effect of the temperature and the storage of plasma sample on Prothrombin Time (PT) and Activated Partial Thromboplastin Time (aPTT) in clinical samples for 65 patients without coagulation disorders. After centrifugation, plasma of each patient was tested at arrival as part of their routine care and separately aliquoted. Three aliquots were stored at room temperature, 4°C and - 20°C for 24h after collection, two aliquots were stored at 4°C and -20°C for 1 week and one aliquot was stored at -70°C for 1 month. PT from healthy patients was affected at room temperature for 24h and at 4°C for 1 week. For aPTT, the results were statistically different for all the conditions after 24h and at 4°C for 1 week. Results indicate that PT and aPTT can be stored at -70ºC for at least 1 month without any significant changes in the assay result.

Beatriz M ，Beatriz P ，Rita C ，Helena A ，Monica B ... -  《-》

Effect of freezing method and storage at -20 degrees C and -70 degrees C on prothrombin time, aPTT and plasma fibrinogen levels.

Alesci S ，Borggrefe M ，Dempfle CE 《-》

Influence of temperature and time before centrifugation of specimens for routine coagulation testing.

Salvagno GL ，Lippi G ，Montagnana M ，Franchini M ，Poli G ，Guidi GC ... -  《-》