Challenging the 30-min rule for thawed plasma.

BACKGROUND AND OBJECTIVES: Frozen plasma (FP) is thawed prior to transfusion and stored for ≤5 days at 1-6°C. The effect of temperature excursions on the quality and safety of thawed plasma during 5-day storage was determined. MATERIALS AND METHODS: Four plasma units were pooled, split and stored at ≤-18°C for ≤90 days. Test units T30 and T60 were exposed to 20-24°C (room temperature [RT]) for 30 or 60 min, respectively, on days 0 and 2 of storage. Negative and positive control units remained refrigerated or at RT for 5 days, respectively. On Day 5, test units were exposed once to RT for 5 h. Quality assays included stability of coagulation factors FV, FVII, FVIII, fibrinogen and prothrombin time. Bacterial growth was performed in units inoculated with ~1 CFU/ml or ~100 CFU/ml of Serratia liquefaciens, Pseudomonas putida, Pseudomonas aeruginosa or Staphylococcus epidermidis on Day 0. RESULTS: Testing results of all quality parameters were comparable between T30 and T60 units (p < 0.05). Serratia liquefaciens proliferated in cold-stored plasma, while P. putida showed variable viability. Serratia epidermidis and P. aeruginosa survived but did not grow in cold-stored plasma. Positive and negative controls showed expected results. Overall, no statistical differences in bacterial concentration between T30 and T60 units were observed (p < 0.05). CONCLUSION: Multiple RT exposures for 30 or 60 min do not affect the stability of coagulation factors or promote bacterial growth in thawed plasma stored for 5 days. It is therefore safe to expose thawed plasma to uncontrolled temperatures for limited periods of 60 min.

Assessing the inactivation capabilities of two commercially available platelet component pathogen inactivation systems: effectiveness at end of shelf life.

BACKGROUND AND OBJECTIVES: The inactivation capabilities of the two current commercially available pathogen inactivation (PI) systems for platelet components (PC), Mirasol and Intercept, were investigated by determination of the absence of viable bacteria at the end of shelf life by testing the entire contents of the PC by enrichment culture (terminal sterility). METHODS: A pool-and-split method was used, with two treated units and one untreated control per inoculum concentration. Pairs of PC bags were inoculated with a single bacterial species. Three concentrations (n = 2 per concentration), which incremented tenfold, were tested initially based on published data from the manufacturer. Dependent on these results, the concentrations subsequently tested were either increased or decreased until the inactivation capability of the system was derived. Bacterial count was determined post-spiking, immediately prior to treatment (2 h from spiking), immediately after treatment and at the end of shelf life (day seven). Enrichment culture was performed immediately prior to treatment, after treatment and at the end of shelf life. RESULTS: The inactivation capabilities, in CFU/ml, of Intercept and Mirasol, respectively, at the end of PC shelf life were as follows: Staphylococcus aureus ≥ 107 , <101 ; Staphylococcus epidermidis ≥106 , <102 ; Klebsiella pneumoniae 105 , <101 ; Streptococcus bovis ≥107 , 101 , Escherichia coli ≥106 , <101 ; Streptococcus pneumoniae ≥106 , 103 ; Streptococcus mitis ≥107 , 101 ; Listeria monocytogenes ≥107 , 101 ; Streptococcus dysgalactiae ≥107 , <101 ; Serratia marcescens 103 , <101 ; Pseudomonas aeruginosa 103 , Mirasol not tested; and Bacillus cereus < 102 , Mirasol not tested. CONCLUSION: The inactivation capability of Intercept was greater than that of Mirasol. Inactivation capability (by terminal sterility) is the most meaningful measure to evaluate a PI system for bacteria, rather than logarithmic reduction assessed immediately after treatment by plate count. PI offers a possible alternative to bacterial screening if treatment is performed at an appropriate time dependent on the inactivation capabilities of the system.