Effects of Freeze-Thaw Times on Screening Coagulation Tests and Factors VIII and IX Activities in Citrate-Anticoagulated Plasma at -20°C and -80°C

Abstract

Background: Accurate determination of screening coagulation tests and factors VIII and IX activities (FVIII:C and FIX:C) in fresh plasma is very important for diagnosing abnormalities in the intrinsic or extrinsic coagulation pathways and factor deficiencies. If thawed samples cannot be detected for all required items at the same time, or need to be re-tested or restored , the thawed samples need to be re-frozen. We planned to perform in-house validation studies on freeze-thawed samples for screening coagulation tests, FVIII:C and FIX:C. Methods: Mean percent changes, numbers of samples with > 10% changes, and difference plots were evaluated to determine clinically relevant differences between results for fresh and freeze-thawed samples. The statistical significance of differences between repeated-measure multiple groups and baseline values were evaluated by repeated-measures analysis of variance. Results: The acceptable freeze-thaw cycles for activated partial thromboplastin time, fibrinogen, prothrombin time/international normalized ratio, thrombin time, and FIX:C were three times at-20°C/-80°C, while the acceptable freeze-thaw cycles for FVIII:C were three times at-80°C and once at-20°C. Conclusions: The freeze-thaw results on stabilities were affected by time and temperature, with lower temperature and fewer times associated with more stable activity.

Freeze‐dried plasma: From damage control resuscitation to coronavirus disease 2019 therapy

“…On the other hand, to avoid the effects of multiple freezethaws on coagulation tests and factor activities, freezethaw cycles for all samples were less than three times. 42 Given the extensive crosstalk between immune and coagulation systems, which occurs at the level of all components of the hemostatic response (including vascular endothelial cells, platelets, plasma coagulation cascade, physiologic anticoagulants, and fibrinolytic activity), we extended our analysis beyond the hemostatic profiles to assess the immunological activities (including inflammatory mediator profiles) that have only rarely been measured in FDP. 18 There was no significant difference in anti-SARS-CoV-2 IgG level and neutralization activity before and after freeze-drying, suggesting its potential use for combat and production of purified antibodies against COVID-19.…”

“…Given that the pre‐COVID‐19 samples have been stored at −80°C for more than one year, some labile clotting factors (e.g., factors V and VIII) might lose their activities. On the other hand, to avoid the effects of multiple freeze‐thaws on coagulation tests and factor activities, freeze‐thaw cycles for all samples were less than three times 42 …”

Plasma Isoagglutinin Depletion for Blood Group Independent Plasma Transfusion

“…The quality of the isoagglutinin-depleted plasma remains high. Despite the double freezing and thawing process during manufacturing, clotting factor V, VIII, and XI activity was preserved and within the specification range of conventional fresh frozen plasma [ 25 ]. Although we depleted all red cells used for adsorption, as assessed by the highly sensitive nageotte chamber method, formation of red cell microvesicles and thus the risk of allo-senzitation against erythrocyte antigens cannot be excluded.…”