Evaluation of 6 years of confidential unit exclusion at the Belgian Red Cross Flanders Blood Service.

BACKGROUND AND OBJECTIVES

The effectiveness of the confidential unit exclusion (CUE) as a safety measure to the blood supply is debated. We therefore investigated the usefulness of CUE in our donor population.

METHODS

Data of CUE use, donor deferrals due to different degrees of sexual or blood exposure and data of confirmed positive transfusion-transmissible infection (TTI) markers were analyzed for the study period January 1, 2004 to December 31, 2009.

RESULTS

The CUE user tended to be of young age, male and first time donor whereas the CUE non-responder was more likely to be older, first time donor without a clear sex predilection. CUE had low sensitivity (0·33%) and low positive predictive value (0·02%) in detecting TTI marker positive donations. Of 46 incident cases, one donor designated his pre-conversion donation as CUE positive. 29·6% of the donors deferred due to reported sex or intravenous drug related risk factors on the donor history questionnaire had ticked 'I do practice risk behavior' on the CUE form. Deferrals for all sexual or blood-blood contact related risk factors were 19·2 times higher among CUE positive donors than among CUE negative donors (95% CI, 18·5-19·9).

CONCLUSION

Although CUE use is associated with higher rates of TTI risk, CUE has low efficiency to detect window period donations. Moreover, misuse results in a significant loss of units. Our data indicate a low risk perception among donors, hence efforts should focus on improving donor knowledge of and on donor's responsibility to disclose TTI risk.