Background/Case Studies: Traditional cryoprecipitate (cryo) manufacturing has changed little since first described while cryo’s primary clinical use has shifted with the introduction of Factor VIII concentrates. Cryo is now primarily used as fibrinogen replacement for acquired fibrinogen deficiency and, in fact, newly FDA-approved pathogen reduced cryoprecipitate technology only requires a minimal total fibrinogen content. Given this shift, it is important to explore cryo manufacturing process improvements to increase fibrinogen content. This study explored the effect of water bath thaw versus several different refrigerator thaws (24 hr, 36 hr, 48 hr) on cryo fibrinogen content. To mitigate any donor variability between experimental groups, FFP was pre-pooled and redivided prior to freezing to create homogenous FFP for comparisons.
Study
Design/Methods: Three pairwise thawing experiments were conducted (#1: 1-6 degree C water bath versus 24 hr refrigerator; #2: 24 hr versus 36 hr refrigerator; #3: 24 hr versus 48 hr refrigerator). For each experiment, FFP mostly from known HLA antibody positive whole blood donations was used. Ten units of FFP were pooled creating 2.5 L of homogenous FFP (FFP 10-pool). Each FFP 10-pool was then redivided into ten individual FFP bags of similar weight and frozen. Five FFP from each FFP 10-pool were assigned to manufacture a single traditional cryo pool per institutional standard operating procedure using that study arm’s assigned thaw methodology. In total, ten FFP 10-pools were used for each pairwise thawing experiment to create ten pairs of cryo pools for comparison. Samples of each original FFP 10-pool and resulting pair of cryo pools were tested for fibrinogen concentration via the Clauss methodology (cryo pool samples required dilution before testing) and total product fibrinogen content was calculated. Cryo pool fibrinogen content was compared between groups using the paired t-test.
Results/Findings: 24 hr refrigerator thaw generated significantly higher cryo pool fibrinogen content than water bath thaw (40% greater; Table 1). Both 36 hr and 48 hr refrigerator thaw generated significant but more modest gains in cryo pool fibrinogen content than 24 hr refrigerator thaw (8% and 11% greater respectively). Conclusions: 24 hr refrigerator thaw leads to significantly higher cryo pool fibrinogen content than water bath thaw and refrigerator thawing times beyond 24 hr lead to smaller further increases. Creating homogenous FFP pools prior to freezing is an effective approach to eliminate donor variability between comparison groups and permit more powerful matched statistical analyses.
Importance of research: Current clinical use of cryoprecipitate is for fibrinogen replacement. Optimization of the manufacture process to increase fibrinogen content is vital for clinical care. Using a novel approach of pre-pooling fresh frozen plasma and redividing prior to freezing, cryoprecipitate manufacture using a refrigerator thaw yielded higher fibrinogen content than a water bath thaw. This pre-pooling technique removes any donor-specific differences between groups and permits matched statistical analyses.
