The Risk of Bacterial Growth in Units of Blood that Have Warmed to More Than 10 °C

Abstract

Most transfusion services discard unopened units of blood that have been returned to the blood bank more than 30 minutes after the issuance or have attained a temperature of more than 10 degrees C. The objective of this study was to learn the prevalence of bacterial growth, if any, in the units of blood that were exposed twice, for six hours each time, to room temperature during their refrigerated storage. All of the 396 units cultured were negative except one red cell unit that grew a Bacillus species, probably B. subtilis. Further studies suggested that the growth of B. subtilis was due to laboratory contamination. The authors concluded that more work is needed to study the bacterial growth and the effect on red cell enzymes in the units of blood that are exposed to room temperature for varying periods or are returned to the blood bank after 30 minutes of issuance. If no adverse effect is noted, the policy of not reissuing such units may need revision so that more units could be salvaged.

Bacterial growth in red blood cell units exposed to uncontrolled temperatures: challenging the 30‐minute rule

“…Based on our findings that the growth of mesophilic and psychrophilic fast‐growing bacteria is not affected by RT exposure, and that there is no differential growth between psychrophilic pathogenic bacteria in RBC units exposed for 30 or 60 min, we propose that an extension of the 30‐min rule to 60 min is reasonable. Extending the 30‐min rule to 1 or 2 h has also been proposed by others . Brunskill et al .…”

New insulation technology provides next‐generation containers for “iceless” and lightweight transport of RBCs at 1 to 10°C in extreme temperatures for over 78 hours

“…4 However, most transfusion services will discard units that are returned more than 30 minutes after they were issued. 5,6 Three key features combine to result in the success of the technology described in these studies. First, the TIC and lid filled with the integrated PCM ensure that a uniform temperature is maintained throughout the container.…”

“…Although units exposed to room temperature for up to 24 hours have reduced storage time based on ATP concentrations and glucose consumption, there appears to be no increased risk of contaminating bacteria that may have survived refrigeration, and other laboratory assay values remain within a normal range. 5,6,9,10 It is therefore possible that in situations where the TIC cannot be 'recharged' after 3 or 4 days, RBCs with temperatures above 10∞C but not higher than 24∞C could be transfused without causing harm to the recipient. However, this practice should be restricted to situations when oxygen-carrying capacity is urgently needed, and the only other option available is no transfusion at all.…”

The viability of autologous human red cells stored in additive solution 5 and exposed to 25°C for 24 hours

“…The actual data on which this “30‐minute rule” was based showed that units of whole blood in plastic bags warmed to temperatures above 10°C in 45 to 60 minutes after removal from blood bank refrigerators 15 . In the ninth edition of the Technical Manual , the justification for the rule was stated: “Warming the blood beyond...(10°C), even with subsequent cooling, tends to accelerate red cell metabolism, produce hemolysis, and may permit bacterial growth in the unit.” 16 (p 49‐50) Bacteria growth in warmed units of RBCs is rare 17 …”