Surrogate markers and their correlation to bacterial contamination and other quality parameters in random-donor platelets by platelet-rich plasma method

Abstract

Introduction: Bacterial contamination in platelet concentrates (PCs) occurs more frequently than other blood components because of several factors such as storage in oxygen permeable blood bags at 20°C–24°C with continuous agitation which facilitates bacterial growth compared to other blood components which are kept frozen or refrigerated which inhibits bacterial proliferation in them. The purpose of the study was to assess the incidence of bacterial contamination of random-donor PCs and factors associated with its contamination and see how well the surrogate markers such as pH and swirling correlate with the same. Methodology: This was a cross-sectional study which included randomly chosen 500 random-donor platelets (RDPs) in blood bank prepared by platelet-rich plasma method. The samples chosen for the study were from the RDPs on the 5th day of storage after their preparation. pH, platelet count, and swirling in platelets, which act as surrogate markers for bacterial contamination, were checked on the RDP units. About 1–3 ml of PCs was inoculated from the RDP units into labeled culture bottles (BD Bactec Peds Plus/F). Results: Among a total of 499 random-donor PCs that were cultured in the automated BACTEC system for the study, none of them were culture positive. Thirty RDP units in the study were visibly lipaemic whereas 93 RDP units were visibly reddish in appearance. PCs having volumes 70 ml did not affect the swirling, pH, and platelet counts. There was a statistically significant difference between mean pH with RDP units having swirling Grade 2 and 3 and platelet counts with RDP units having swirling Grade 1 and 2. Conclusion: Bacterial contamination though poses a significant risk is a very rare event in a meticulously prepared and stored PCs. Surrogate markers though useful in resource-constrained settings does not correlate optimally with the quality indicators.