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

S.O.S. - Save our supplies: Understanding reasons to tackle the challenge of wasted returned blood products

OBJECTIVES

To evaluate the return of blood components across different hospital areas, reasons for the same and suggest preventive strategies which might reduce out of controlled temperature storage (CTS) blood logistics and wastage.

MATERIAL AND METHODS

A retrospective audit was carried out in the department of Transfusion Medicine from January 2019 to December 2022. Data related to returned blood components was compiled using departmental records and blood centre software entries.

RESULTS

A total of 218 instances of returned components were noted and the total number of components returned were 442 (0.4% of all issued components) (38.4% (170) packed red blood cells, 16.2% (72) single donor cryoprecipitate concentrate, 19.6% (87) platelet concentrate and 25.5% (113) fresh frozen plasma). Components were returned back within 30 mins in only 27% (59/218) of all instances . Wards followed by high dependency units/intensive care units were noted to have the highest number of instances (86 (39.4%) and 69 (31.6%) respectively) with emergency department having the least,comprising 19 instances (8.7%). 77.9% (170/218) instances were observed for routine transfusion requests and 44.5% (97/218) of all instances could have been prevented by an appropriate clinical status assessment of the patient.

CONCLUSION

Stakeholders such as clinicians, transfusion laboratory professional and nursing staff must take consolidated efforts to eliminate wastage of blood components. Instances of returned blood components can be targeted by the hospital quality team as a quality improvement project.

Growth and Distribution of Bacteria in Contaminated Whole Blood and Derived Blood Components

Introduction

Bacterial contamination of blood products presumably occurs mainly during blood collection, starting from low initial concentrations of 10-100 colony-forming units (CFUs) per bag. As little is known about bacterial growth behavior and distribution in stored whole blood (WB) and WB-derived blood products, this study aims to provide data on this subject.

Methods

WB units were inoculated with transfusion-relevant bacterial species (Acinetobacter baumannii, Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, Listeria monocytogenes, Pseudomonas fluorescens, Serratia marcescens, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus dysgalactiae, Streptococcus pyogenes, Yersinia enterocolitica; n = 12 for each species), stored for 22-24 h at room temperature, and then centrifuged for separation into plasma, red blood cells (RBCs), and buffy coats (BCs). The latter were pooled with 3 random donor BCs and one unit of PAS-E each to yield plasma-reduced platelet concentrates (PCs). Samples for bacterial colony counting were collected after WB storage and immediately after blood component production. Sterility testing in PCs (n = 12 for each species) was performed by bacterial culture after 7 days of storage.

Results

Bacterial growth in WB varied remarkably between donations and species. Streptococcus species produced the highest titers in WB, whereas Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas fluorescens did not multiply. Centrifugation resulted in preferential accumulation of bacteria in BCs, with titers of up to 3.5 × 103 CFU/mL in BCs and up to ≤0.9 × 103 CFU/mL in BC-derived PCs. Overall, 72/144 PCs (50%) tested positive for bacteria after storage. Sterility test results were species-dependent, ranging from 12 of 12 PCs tested positive for Streptococcus pyogenes to 1 of 12 PCs positive for Escherichia coli. Bacterial contamination of RBC and plasma units was much less common and was associated with higher initial bacterial counts in the parent WB units.

Conclusions

Bacterial growth in WB is species-dependent and varies greatly between donations. Preferential accumulation of bacteria in BCs during manufacturing is a critical determinant of the contamination risk of BC-derived pooled PCs.

In vitro quality and hemostatic function of cold-stored CPDA-1 whole blood after repeated transient exposure to 28°C storage temperature

Background

Blood products are frequently exposed to room temperature or higher for longer periods than permitted by policy. We aimed to investigate if this resulted in a measurable effect on common quality parameters and viscoelastic hemostatic function of cold stored CPDA‐1 whole blood.

Study Design and Methods

450 ml of whole blood from 16 O Rh(D) positive donors was collected in 63 ml of CPDA‐1 and stored cold. Eights bags were exposed to five weekly 4‐h long transient temperature changes to 28°C. Eight bags were stored continuously at 4°C as a control. Samples were collected at baseline on day 1, after the first cycle on day 1 and weekly before each subsequent cycle (day 7, 14, 21, 28 and 35). Hemolysis, hematological parameters, pH, glucose, lactate, potassium, thromboelastography, INR, APTT, fibrinogen, and factor VIII were measured.

Results

CPDA‐1 whole blood repeatedly exposed to 28°C did not show reduced quality compared to the control group on day 35. Two units in the test group had hemolysis of 1.1% and 1.2%, and two in the control group hemolysis of 0.8%. Remaining thromboelastography clot strength (MA) on day 35 was 51.7 mm (44.8, 58.6) in the test group and 46.1 (41.6, 50.6) in the control group (p = .023). Platelet count was better preserved in the test group (166.7 [137.8, 195.6] vs. 117.8 [90.3, 145.2], p = .018). One sample in the test group was positive for Cutibacterium acnes on day 35 + 6.

Conclusion

Hemolysis findings warrant further investigation. Other indicators of quality were not negatively affected.

Assessment of bacterial growth in leukoreduced cold-stored whole blood supports overnight hold at room temperature prior to filtration: A pilot study

BACKGROUND AND OBJECTIVES

Whole blood (WB) transfusion has regained attention to treat trauma patients. We reported no significant changes in in vitro quality through 21 days of cold storage for leukoreduced WB (LCWB) when time to filtration was extended from 8 to 24 h from collection. This study evaluated the impact of extended WB-hold at room temperature (RT) prior to leukoreduction on proliferation of transfusion-relevant bacteria.

MATERIALS AND METHODS

WB units were spiked with suspensions of Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus and Listeria monocytogenes prepared in saline solution (SS) or trypticase soy broth (TSB) to a concentration of ~0.2 CFU/ml (N = 6). Spiked units were held at RT for 18-24 h before leukoreduction and cold-stored for 21 days. Bacterial growth was determined on days 2, 7, 14 and 21. In vitro quality of WB inoculated with unspiked diluents was assessed.

RESULTS

K. pneumoniae and S. pyogenes proliferated in WB prior to leukoreduction reaching concentrations ≤10² CFU/ml. These bacteria, however, did not proliferate during the subsequent cold storage. S. aureus did not survive in WB while L. monocytogenes reached a concentration of ~10² CFU/ml by day 21. LCWB in vitro quality was not affected by SS or TSB.

CONCLUSION

Extended WB-hold prior to leukoreduction allowed proliferation of bacteria able to resist immune clearance, although they did not grow to clinically significant levels. While L. monocytogenes proliferated in LCWB, clinically relevant concentrations were not reached by day 21. These data suggest that transfusing LCWB may not pose a significant bacterial contamination safety risk to transfusion patients.

Effect of leukoreduction and temperature on risk of bacterial growth in CPDA-1 whole blood: A study of Escherichia coli

BACKGROUND

Collection of non-leukoreduced citrate-phosphate-dextrose-adenine (CPDA-1) whole blood is performed in walking blood banks. Blood collected under field conditions may have increased risk of bacterial contamination. This study was conducted to examine the effects of WBC reduction and storage temperature on growth of Escherichia coli (ATCC® 25922™) in CPDA-1 whole blood.

METHODS

CPDA-1 whole blood of 450 ml from 10 group O donors was inoculated with E. coli. Two hours after inoculation, the test bags were leukoreduced with a platelet-sparing filter. The control bags remained unfiltered. Each whole blood bag was then split into three smaller bags for further storage at 2-6°C, 20-24°C, or 33-37°C. Bacterial growth was quantified immediately, 2 and 3 h after inoculation, on days 1, 3, 7, and 14 for all storage temperatures, and on days 21 and 35 for storage at 2-6°C.

RESULTS

Whole blood was inoculated with a median of 19.5 (range 12.0-32.0) colony-forming units per ml (CFU/ml) E. coli. After leukoreduction, a median of 3.3 CFU/ml (range 0.0-33.3) E. coli remained. In the control arm, the WBCs phagocytized E. coli within 24 h at 20-24°C and 33-37°C in 9 of 10 bags. During storage at 2-6°C, a slow self-sterilization occurred over time with and without leukoreduction.

CONCLUSIONS

Storage at 20-24°C and 33-37°C for up to 24 h before leukoreduction reduces the risk of E. coli-contamination in CPDA-1 whole blood. Subsequent storage at 2-6°C will further reduce the growth of E. coli.

Establishment of transfusion-relevant bacteria reference strains for red blood cells

BACKGROUND AND OBJECTIVES

Red blood cell concentrates (RBCC) are susceptible to bacterial contamination despite cold storage. A reliable evaluation of strategies to minimize the risk of RBCC-associated bacterial transmission requires the use of suitable reference bacteria. Already existing Transfusion-Relevant Bacteria Reference Strains (TRBRS) for platelet concentrates fail to grow in RBCC. Consequently, the ISBT TTID, Working Party, Bacterial Subgroup, conducted an international study on TRBRS for RBCC.

MATERIALS AND METHODS

Six bacterial strains (Listeria monocytogenes PEI-A-199, Serratia liquefaciens PEI-A-184, Serratia marcescens PEI-B-P-56, Pseudomonas fluorescens PEI-B-P-77, Yersinia enterocolitica PEI-A-105, Yersinia enterocolitica PEI-A-176) were distributed to 15 laboratories worldwide for enumeration, identification, and determination of growth kinetics in RBCC at days 7, 14, 21, 28, 35 and 42 of storage after low-count spiking (10-25 CFU/RBCC).

RESULTS

Bacterial proliferation in RBCC was obtained for most strains, except for S. marcescens, which grew only at 4 of 15 laboratories. S. liquefaciens, S. marcescens, P. fluorescens and the two Y. enterocolitica strains reached the stationary phase between days 14 and 21 of RBCC storage with a bacterial concentration of approximately 10⁹  CFU/ml. L. monocytogenes displayed slower growth kinetics reaching 10⁶ -10⁷  CFU/ml after 42 days.

CONCLUSION

The results illustrate the importance of conducting comprehensive studies to establish well-characterized reference strains, which can be a tool to assess strategies and methods used to ameliorate blood safety. The WHO Expert Committee on Biological Standardization adopted the five successful strains as official RBCC reference strains. Our study also highlights the relevance of visual inspection to interdict contaminated RBC units.

Compliance with temperature and time requirements during in-hospital distribution of blood components: A national survey among transfusion services

INTRODUCTION

Temperature and time conditions during storage and distribution of blood components (BC) and their permissible deviations are strictly regulated. The degree of compliance with these requirements in daily practice of transfusion services (TS) is not well known.

MATERIALS AND METHODS

We conducted a survey among Spanish hospital TS covering different aspects of BC management in their daily activity.

RESULTS

Eighty-three TS managing 56 % of total transfusions answered the survey. Monitoring of red blood concentrates (RBC) temperature during in-hospital distribution was routinely performed by only 12 % of the TS. The main criterion for BC re-entry into the stock was the total time spent outside controlled temperature. Up to 41 % of the TS apply the "30-minute rule" to distributed RBC, while most services use a 60-minute rule for PC. No adverse events were detected when RBC that had remained longer than 30 or 60 min outside the TS were transfused. Fresh frozen plasma is usually thawed 2 h preissue and stored at 4 °C up to 24 h.

DISCUSSION AND CONCLUSIONS

In the Spanish context, the 30- and 60-minute rules for re-entry of RBC and PC into the TS stock are loosely followed. Feedback for a large number of TS suggests that the extension of the 30-minute RBC rule to at least 60 min is feasible, if other safety requirements are met. Flexibility with some requirements could help reduce product loss without deleterious effect on BC safety.

Bacterial contamination of blood products for transfusion in the Democratic Republic of the Congo: temperature monitoring, qualitative and semi-quantitative culture

BACKGROUND

Bacterial contamination of blood for transfusion is rarely investigated in low-income countries. We determined the contamination rate of blood products in the Democratic Republic of the Congo.

MATERIAL AND METHODS

In this prospective observational study, blood products in one rural and two urban hospitals (paediatric and general) contained a satellite sampling bag by which blood was sampled for culture in a blood culture bottle (4 mL) and on an agar-coated slide to estimate colony forming units (CFU/mL). Bacteria were identified with biochemical tests and MALDI-TOF (Bruker). Exposure time >10 °C was assessed on a subset of blood products.

RESULTS

In total, 1.4% (41 of 2,959) of blood products were contaminated with 48 bacterial isolates. Skin (e.g., Staphylococcus spp.) and environmental (e.g., Bacillus spp.) bacteria predominated (97.8% of 45 isolates identified). Bacterial counts were ≤10³ CFU/mL. Contamination rates for the urban paediatric, urban general and rural hospitals were 1.6%, 2.4% and 0.3%, respectively (p=0.004). None of the following variables was significantly associated with contamination: (i) donor type (voluntary 1.6%, family 1.2%, paid 3.9%); (ii) type of blood product (red cells 1.6%, whole blood 0.6%); (ii) season (dry season 2.4%, rainy season 1.8%); (iv) age of blood product (contaminated 8 days vs non-contaminated 6 days); and (v) exposure time >10 °C (median for contaminated and non-contaminated blood reached maximum test limit of 8 hours).

DISCUSSION

A bacterial contamination rate of 1.4% of whole blood and red cells is similar to results from high-income countries. Implementation of feasible risk-mitigation measures is needed.

Logistical and safety implications of temperature-based acceptance of returned red blood cell units

BACKGROUND

AABB requires that red blood cells (RBCs) are maintained at 1 to 10°C during transport. Historically, blood banks used the 30-minute rule for returned RBCs transported outside of validated containers. The implications of this policy have not been previously reported in a real-life hospital setting.

STUDY DESIGN AND METHODS

A 2-year, retrospective review of RBC units returned outside of qualified containers was conducted. During the first year, the 30-minute rule was used to accept RBCs back into inventory. Sequentially, the following year, a temperature-based approach was implemented using a thermometer with an accuracy of ±1°C. Time out of the blood bank, temperature upon return, wastage, and transfusion reactions associated with the reissued RBCs were analyzed.

RESULTS

In our practice, the 30-minute rule would have accepted 15.2% of RBC units outside of the allowed temperature. Compared to the 30-minute rule, temperature-based acceptance was associated with a 13% increase in wastage (p < 0.001). During the 30-minute rule period, transfusion of returned and subsequently reissued RBCs was associated with a nonsignificant trend toward a higher transfusion reaction rate compared to the overall RBC transfusion reaction rate (1.4% vs. 0.6%, p = 0.084). During the temperature period, transfusion of returned and subsequently reissued RBCs had the same transfusion reaction rate compared to the overall RBC transfusion reaction rate (0.5% vs. 0.5%, p = 1.0).

CONCLUSION

Temperature-based acceptance of returned RBCs is associated with significantly higher wastage compared to the 30-minute rule. A temperature-based acceptance practice mitigates the risk of accepting RBCs with unacceptable temperatures returned within 30 minutes of issue.

Non-invasive spectroscopy of transfusable red blood cells stored inside sealed plastic blood-bags

After being separated from (donated) whole blood, red blood cells are suspended in specially formulated additive solutions and stored (at 4 °C) in polyvinyl chloride (PVC) blood-bags until they are needed for transfusion. With time, the prepared red cell concentrate (RCC) is known to undergo biochemical changes that lower effectiveness of the transfusion, and thus regulations are in place that limit the storage period to 42 days. At present, RCC is not subjected to analytical testing prior to transfusion. In this study, we use Spatially Offset Raman Spectroscopy (SORS) to probe, non-invasively, the biochemistry of RCC inside sealed blood-bags. The retrieved spectra compare well with conventional Raman spectra (of sampled aliquots) and are dominated by features associated with hemoglobin. In addition to the analytical demonstration that SORS can be used to retrieve RCC spectra from standard clinical blood-bags without breaking the sterility of the system, the data reveal interesting detail about the oxygenation-state of the stored cells themselves, namely that some blood-bags unexpectedly contain measurable amounts of deoxygenated hemoglobin after weeks of storage. The demonstration that chemical information can be obtained non-invasively using spectroscopy will enable new studies of RCC degeneration, and points the way to a Raman-based instrument for quality-control in a blood-bank or hospital setting.

Changing the 30-min Rule in Canada: The Effect of Room Temperature on Bacterial Growth in Red Blood Cells

BACKGROUND

To maintain product quality and safety, the '30-min rule' requires the discard of red blood cells (RBCs) that are exposed to uncontrolled temperatures for more than 30 min. Recent studies suggest this rule may safely be extended to a 60-min rule.

METHODS

A pool-and-split design study (N = 4) was run in parallel at Canadian Blood Services (SAGM RBCs) and Héma-Québec (AS-3 RBCs). RBCs were spiked with ∼1 colony-forming unit/ml of mesophilic and psychrophilic bacteria. Control units remained in storage at 1-6 °C for 42 days. Test 30 (T30) and T60 units were exposed to room temperature (RT) six times during storage, each time for 30 and 60 min, respectively. Bacterial proliferation was monitored.

RESULTS

Mesophilic bacteria do not proliferate in RBCs. The growth of psychrophilic bacteria is not significantly different in RBCs exposed for 30 or 60 min to RT (p < 0.05).

CONCLUSION

The study findings were the final evidence to support extension from a 30-min rule to a 60-min rule in Canada.

Temperature-Sensitive Indicators for Monitoring RBC Concentrates Out of Controlled Temperature Storage

OBJECTIVES

The 30-minute rule for RBC concentrates out of controlled temperature storage does not take into account multiple parameters that influence warming of RBC concentrates. This study evaluated two temperature-sensitive indicators (TIs) for monitoring RBC concentrates during transport.

METHODS

TI labels (Check-Spot [Harald H. Temmel KG, Gleisdorf, Austria] and Thermoindikator V4 [BASF, Basel, Switzerland]) were attached to RBC concentrates prior to delivery. Duration of transport, ambient temperatures, and label results (valid vs expired) were recorded. We evaluated the proportion of labels discrepant to the 30-minute rule overall and among deliveries 30 minutes or less and more than 30 minutes and compared the rates of valid and expired readings between both TIs.

RESULTS

In total, 201 RBC concentrate deliveries (86.6%) lasted 30 minutes or less, and 31 (13.4%) were more than 30 minutes. Forty-six (19.8%) Check-Spot and 37 (15.9%) Thermoindikator V4 results were discrepant to the 30-minute rule. Sixteen (51.6%) and 27 (87.1%) RBC concentrate deliveries more than 30 minutes displayed valid label readings with Check-Spot and Thermoindikator V4, respectively. Rates of expired labels among deliveries 30 minutes or less and valid labels among deliveries more than 30 minutes differed significantly between TIs (P < .01).

CONCLUSIONS

TIs identified a considerable number of RBC concentrates whose temperatures may not be adequately reflected by the 30-minute rule. Variability of readings between TIs stresses the necessity of validation prior to implementation.

Effectiveness of multiple initiatives to reduce blood component wastage

OBJECTIVES

Blood component waste is an important issue at all hospitals. As an initiative of the patient blood management program at a regional health care system, the causes and extent of blood product wastage were identified, and targeted interventions to effect a reduction were implemented.

METHODS

Multiple low-cost interventions, including educational outreach, print and digital messaging, and improved transportation and component identification modalities, were implemented beginning in January 2013. The impact on reducing RBC, platelet (PLT), and plasma wastage in the 16 months after intervention implementation was compared with the wastage rates in the 16 months before these interventions had been implemented.

RESULTS

Overall, the RBC wastage rate as a percentage of the number of units issued decreased from 0.67% to 0.56% (P = .001) after the interventions were implemented, while the PLT wastage rate decreased from 3.71% to 2.81% (P < .001). The plasma wastage rate increased from 1.14% to 1.40% (P < .001). The initial cost of these interventions was approximately $310. The net cost savings of the reduced waste was estimated at $131,520, excluding intervention costs.

CONCLUSIONS

Relatively inexpensive interventions can have a prompt and dramatic impact on reducing blood wastage with regard to both cost and resource savings.

Storage and handling of blood components – perspectives

The storage and handling conditions of cellular blood components and plasma are often rigorous, which is causing extensive discard of components that may be of acceptable quality as the rules for “out of optimal storage conditions” seem to be based more on tradition than scientific investigations. This short review summarizes some of the key papers indicating that it should be time for reconsideration of these rules, and some new suggestions are carefully indicated. Red cell concentrates, platelet concentrates and FFP are considered;lyophilized plasma and never-frozen liquid plasma are not included in this paper.

Quality and safety of red blood cells stored in two additive solutions subjected to multiple room temperature exposures

BACKGROUND AND OBJECTIVES

Many international standards state that red blood cell (RBC) products should be discarded if left out of controlled temperature storage for longer than 30 min to reduce the risk of bacterial growth and RBC loss of viability. This study aimed to verify whether repeated short-time exposures to room temperature (RT) influence RBCs quality and bacterial proliferation.

MATERIALS AND METHODS

Saline-adenine-glucose-mannitol (SAGM) and AS-3 RBC units were split and exposed to RT for 30 or 60 min on day 2, 7, 14, 21, and 42 of storage while reference units remained stored at 1-6°C. Red blood cell in vitro quality parameters were evaluated after each exposure. In a second experiment, SAGM and AS-3 RBC units were split and inoculated with Staphylococcus epidermidis (5 CFU/ml), Serratia marcescens (1 CFU/ml), and Serratia liquefaciens (1 CFU/ml). Reference units remained in storage while test units were exposed as described previously. Bacterial concentrations were investigated after each exposure.

RESULTS

No differences were noticed between reference and test units in any of the in vitro parameters investigated. S. epidermidis did not grow in either reference or exposed RBCs. While S. marcescens did not grow in AS-3, bacterial growth was observed in RT-exposed SAGM RBCs on day 42. Similar growth was obtained for S. liquefaciens in the two additive solutions for both reference and test units.

CONCLUSION

Short-time exposures to RT do not affect RBC quality and do not significantly influence bacterial growth. An expansion of the '30-minute' rule to 60 min should be considered by regulatory agencies.

Impact of constant storage temperatures and multiple warming cycles on the quality of stored red blood cells

BACKGROUND

Red blood cells (RBCs) are routinely stored in liquid state at temperatures below 6°C, and RBC unit core temperature should not exceed 10°C during transport. Since the critical temperature of 10°C was chosen mostly arbitrarily, this study investigated the effect of both constant temperature settings as well as multiple rewarming cycles on stored RBCs with respect to morphology, biochemical parameters and haemolysis.

MATERIALS AND METHODS

Buffy coat-depleted filtered RBCs were used as standard products. RBCs were stored at 1-6°C (reference group, n = 12), 13 and 22°C (test groups, n = 12 each) or stored at 1-6°C and warmed up five times to 10, 13, or 22°C for a period of 24 h each. Various biochemical parameters were measured weekly. RBCs were further investigated using electron microscopy.

RESULTS

Red blood cells stored constantly at 13 or 22°C showed stable haemolysis rates until day 28 and day 14, respectively. RBCs stored at 1-6°C with five warming-up periods to 10, 13 or 22°C each lasting 24 h (total 120 h) did not exceed the limit of the haemolysis rate at the end of storage. Differently shaped erythrocytes were found in all samples, but more crenate erythrocytes appeared after 42 days of storage independent of temperature profiles.

CONCLUSION

Red cells can be kept at constant temperatures above 6°C without apparent harmful effects at least until day 14, whereas multiple warming cycles for no longer than 24 h at 10, 13 or 22°C with subsequent cooling do not cause quality loss as assessed using the in vitro assays employed in this study.