The American Red Cross performs laboratory tests for multiple infectious disease markers on every unit of donated blood. Tests are upgraded or replaced with more sensitive technologies as these become available. These tests include:
Anti-Trypanosoma cruzi
Hepatitis B virus (HBV)
Hepatitis C virus (HCV 3.0)
Human Immunodeficiency viruses, Types 1 and 2 (HIV 1,2)
Human T-Lymphotropic virus (HTLV-I/II)
Syphilis (Treponema pallidum)
West Nile virus (WNV)
If your partner was positive for HIV, it would DEFINITELY be found and he would be notified.