Donor return after temporary deferral.

Area of Science:

• Blood Transfusion Medicine
• Public Health
• Epidemiology

Background:

• The impact of temporary deferral on blood donor return rates is not fully understood.
• Existing studies suggest deferral negatively affects donor persistence, but generalizability across donation centers is unclear.

Purpose of the Study:

• To investigate the relationship between temporary deferral categories and subsequent blood donor return.
• To identify donor characteristics associated with return after deferral across multiple US donation centers.

Main Methods:

• A cohort study followed nearly 4 million donor presentations from 2006-2008 across six US blood centers.
• Donors deferred into six categories (e.g., low hematocrit, blood pressure, travel) were tracked for up to three years post-deferral.
• Time-to-event analysis and multivariable logistic regression assessed return rates and influencing factors.

Main Results:

• Low hematocrit deferrals were most common, showing the quickest return and highest cumulative return proportion.
• Shorter deferral durations correlated with better donor return rates.
• Longer deferrals (up to one year) resulted in less than 50% donor return.
• Repeat donor status, older age, higher education, US birth, and fixed-site donation were associated with return, irrespective of deferral type.

Conclusions:

• The specific reason for temporary deferral influences a blood donor's likelihood to return.
• Demographic and donation site factors consistently predict donor return across different deferral categories.