Safety of the blood supply is a top priority. After collection, blood donations are tested in accredited laboratories to screen for infectious agents and to confirm blood type. These tests reduce the risk of transfusion-transmitted infections to very low levels.
Common tests
Typical screening includes tests for HIV, hepatitis B and C, syphilis, and other locally relevant infections. Many services also perform additional molecular tests (NAT) which can detect infections earlier than antibody tests.
Quality control
Laboratories follow strict quality assurance processes: controls, validated reagents, and periodic proficiency testing. Units that fail any test are discarded and donors are notified when appropriate and supported with counselling and referral.
Lookback and traceability
Blood banks maintain records so any issues can trigger a 'lookback' to identify and manage potentially affected recipients. Traceability ensures units can be tracked from donor to transfusion location.
Testing protocols vary slightly by country and service. For precise details consult your national blood service or regional laboratory guidelines.