Donor Screening and Infectious Disease Testing
Required tests on every donation
Serology: HBsAg, total anti-HBc, anti-HCV, anti-HIV-1/2, anti-HTLV-I/II, and a syphilis test. Nucleic acid testing: HIV-1, HCV, HBV, West Nile virus (seasonal and regional), plus Babesia in endemic areas and Zika where applicable. Anti-CMV testing is not required but is used to select CMV-negative units; leukoreduction is an accepted alternative. Every test must be FDA-licensed and performed on every donation, and any reactive result quarantines the unit.
Donor screening and deferral
The questionnaire covers infection risk, medications, travel, incarceration, and high-risk behavior. Representative deferrals: high-risk sexual behavior or sex between men (3 months), unregulated tattoos or piercings (3 months), malaria travel (12 months), live vaccines (2-4 weeks), pregnancy (6 weeks postpartum), most cancers (often permanent), and HIV, HCV, or HBV infection (permanent). Confidential unit exclusion and post-donation information allow donors to self-defer.
Window periods and lookback
Nucleic acid testing shortens window periods to roughly 9-11 days for HIV, about 7 days for HCV, and 20-25 days for HBV. Lookback traces prior donations from a donor who later tests positive and notifies recipients; involved components are quarantined and destroyed, and samples are retained.
Traps
- Isolated anti-HBc reactivity does not prove active hepatitis B but frequently causes donor loss.
- A negative serologic test does not exclude recent infection, which is precisely why NAT is performed.
- Bacterial contamination of platelets is the leading residual infectious risk because viral screening does not detect it; culture-based detection is required.
Rule of thumb: every donation is tested every time by both serology and nucleic acid testing, and donor history never substitutes for a test result.