Definition
An infection following a transfusion, where there was none before and no alternative source of infection, and at least one component transfused came from a donor with the same transmissible infection, or was shown to contain the agent of infection.
Transfusion-Transmitted Infection (TTI) may be bacterial, viral, or other such as prions, protozoa and filaria.
Frequency
Variable depending on type of infection but most are Extremely Rare (<1/1 million). The risk can never be removed completely.
In the last 10 years, between 0-5 TTIs have been confirmed each year, in the context of over 2 million units of blood components issued per year from the UK blood services to hospitals.
Reducing the risk
Bacterial
• visual inspection of component for contamination at issue and at administration
• administration using aseptic non-touch technique
• temperature-controlled storage
• adherence to expiry date and time
• bacterial monitoring (for platelets)
Viral
• donor health check
• screening of donations: HIV, HBV, HCV, Syphilis, HTLV, HEV
• not all blood components have been screened for cytomegalovirus (CMV);
if your patient requires CMV negative components, make sure this is identified
on the blood request, transfusion instruction, and patient's records
• donations are not currently screened for Parvovirus B19. This virus could potentially be transmitted via transfusion, however the likelihood of acquiring the infection via community spread is far greater.
The UK blood services undertake continuous surveillance for emerging infections which might have potential for transmission via transfusion.
Additional safeguards are rapidly introduced to respond to any new threats. For latest updates click here.
Further information/ resources
SHOT Bite No.7a: Reporting and investigating bacterial Transfusion Transmitted Infections (TTI)
SHOT Bite No.7b: Reporting and investigating non-bacterial Transfusion Transmitted Infection (TTI)
SHOT Transfusion Transmitted Infection Cumulative Data
Up to date data on transfusion transmitted infection risks in the UK, including annual reviews of donor screening, can be found here:
NHS Blood and Transplant / UK Health Security Agency Epidemiology Unit