10.6: Look-back investigations

Look-back investigations are initiated on recognition that there may have been a risk of transmitting infection from a donor to a recipient. Such a situation may arise in the following circumstances:

• donors identified as infected through the introduction of a new screening test applied to all donations
   
• donors identified to be infected through seroconversion during their blood donation career
   
• donors identified to be infected and reported to the Blood Service from an outside source
   
• donors identified to be responsible for transmission of infection to a recipient.

10.6.1: General principles for look-back investigations

National look-back investigations, following introduction of a new screening test, should be managed through a generic system which incorporates the following steps:

• identification of potentially infectious donations
   
• identification of all blood components prepared from those donations
   
• documentation of the fate of the blood components
   
• notification of hospital transfusion laboratories in receipt of involved blood components
   
• identification of the fate of the component at the hospital, including details of any identified recipient
   
• for recipients not known to be dead, a procedure for notification, generally following notification of the GP/hospital clinician
   
• a protocol for management of recipient notification and testing (if required)
   
• notification of recipient test results to recipient and other interested parties.

Look-back investigations following identification of a donor who has seroconverted and/or been responsible for transmission of infection and/or is identified through post-donation information should be carried out using the same principles.

Wherever possible, retrospective testing of stored samples should be carried out in order to identify those donations which must be included in the look-back. If samples can be tested, look-back should be performed to include the last seronegative donation, unless there is evidence about the timing of infection which would make such action unnecessary, e.g. a documented negative test result after the last negative blood donation, a clear history of risk exposure post-dating the last seronegative donation etc.

If retained samples are not available for testing, then case-by-case decisions on the number of donations to be included in the look-back will be influenced by the dates of donations and the availability of the particular hospital transfusion records.

10.6.2: Documentation and reporting

All cases of look-back should be documented in the same fashion as investigation of TTI. There should be a full audit trail of decisions made and actions taken.

Where look-back results in the identification of infected recipients, a report should be made to the surveillance system as appropriate, and cases included in the annual SHOT report.