Transfusion-Transmitted Infection (TTI)

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.

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 in 1 million).

In the last 10 years, between 0 and 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.

See the Annual Serious Hazards of Transfusion (SHOT) Report 2021 – page 206, Table 20.4.

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.

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. Position Statements are available from JPAC.

Further information and resources

Information:

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