Algorithm for clinical decisions related to positive, negative, and indeterminate findings from human immunodeficiency virus (HIV) Western blot (WB) tests following positive findings from HIV enzyme-linked immunosorbent assay (ELISA). Two to 3 bands constitute a minimally positive WB test result; findings are interpreted with caution since they can be false-positive results. Individuals infected with HIV are unlikely to have positive findings from ELISA and negative findings from the WB test. A polymerase chain reaction (PCR) test is generally unnecessary in such cases but can be considered if there is considerable patient anxiety. The break point between the second and third trimester is artificial and is used for simplicity, meant to distinguish less urgent (early pregnancy) from more urgent (late pregnancy, labor, and delivery) situations. ZDV indicates zidovudine.