Examination of a blood transfusion unit for suspected bacteriological contamination as a cause of a transfusion reaction.
Transfusion reactions can occur from a variety of non-infectious and infectious reasons. Mis-transfusion (blood transfused to other than the intended recipient) may occur as a result of phlebotomy error, incorrect identification of the recipient to the blood unit and technical problems.
Serious or life-threatening acute reactions to blood transfusions are rare, but all new symptoms appearing in the patient while the blood transfusion is taking place must be taken seriously, as they could be the first warning signs of a serious reaction.
Bacterial contamination from transfusion is rare but is more often reported with platelet concentrations (stored at 22°C) than with red cell transfusions (stored at 4 – 6°C). If reaction to the blood transfusion is suspected to be due to a blood pack contaminated with bacteria, then it is likely that the patient will have a very severe acute reaction, with rapid onset of hyper/ hypotension, rigors and collapse. These symptoms are similar to acute haemolytic transfusion reaction and severe acute allergic reaction.
The infectious causes may be bacterial or viral. Contaminating bacteria can proliferate from low concentration at the time of collection to very high concentration (>1x 108 CFU/mL) during liquid storage. Unlike viruses, bacteria can multiply on their own, especially in platelets at 22˚ C; while cryophilic organisms are happy to replicate at blood storage temperature of 4˚C. Yersinia enterocolitica is a significant cause of adverse reaction with red blood cells.
If a transfusion reaction is suspected, the following algorithms should be followed by the ward:
Action A: If any of the following occur during , or within 2 hours of a transfusion:
- Fever (an increase of more than 2°C)
- Tachycardia (heart rate ≥120/min) or an increase in heart rate of >30/min
- Shaking, chills
- Hypotension (drop in systolic blood pressure of more than 30mm Hg)
- Nausea, vomiting, diarrhoea, dyspnoea, bleeding, oliguria or symptoms of shock
Strongly suspicious of a microbiological transfusion reaction – do local microbiological screen plus immediate NHSBT notification plus refer to NHSBT Colindale for their microbiological testing procedure.
If there is a strong suspicion of a microbiological transfusion reaction, the pack will probably be referred directly to Colindale by blood transfusion, without a local microbiological screen.
Action B: Fever – an increase of 1-2°C within the first two hours, but no other symptoms.
A microbiological reaction is a possibility but not probable – do local microbiological screen and only inform NHSBT if this testing proves positive.
Action C: Fever – an increase of less than 1°C but no other symptoms.
A microbiological transfusion reaction is very unlikely – no local microbiological testing or contacting NHSBT.
Entire blood transfusion bag and tubing should be sent.
Microbiology Lab, James Cook University Hospital, Marton Road, TS4 3BW
Please contact the lab prior to sending transfusion reactions for processing.