Re-entry of donors deferred for false-reactive screening tests in Canada: 10 years post implementation

Canadian Blood Services implemented a re-entry programme in 2014. Donors deferred because of false-reactive or indeterminate screening tests can provide a specimen for re-entry testing 6 months after their initial test, and resume donating if they test negative for all infectious markers. We evaluated the impact of the programme on donor return and retention, and assessed factors associated with reactive results upon re-entry testing.

Using extracted data from our donor database, we followed up donors who tested false-reactive for hepatitis B virus (HBV), human immunodeficiency virus (HIV) and hepatitis C virus (HCV), from the implementation of the programme on 3 February 2014 until 30 June 2025 (n = 8094). We characterized the donors reaching each step of the programme by sex, age, donation status and infection marker. We employed logistic regression to identify important predictors of obtaining reactive results upon re-entry testing.

Overall, 17.3% of donors eligible for re-entry testing successfully returned and donated. Re-entry testing participation rates were 35.5%, with repeat and older donors more likely to participate. Among re-entry tested donors, 59.2% tested negative. Most donors continued to donate for multiple years upon re-entry. Upon return, 13.1% tested false reactive on a subsequent donation. False-reactives upon re-entry testing were more likely for first-time donors and less likely when a different assay was employed than for the initially false-reactive.

The implementation of a donor re-entry programme has resulted in donor retention and increases in the blood supply. Sending reminder notifications to eligible donors could increase participation.