Hi, Thanks for writing in. You should always go for post exposure prophylaxis for HIV if suspicious break of condom when having sex wit a prostitute. This itself will reduce the chances of getting HIV. In the earliest stages, DNA or RNA PCR tests are best to diagnose virus particles. This is best done after about a week to 15 days. For presence of antibodies, the main tests for the diagnosis of HIV infection are the HIV enzyme-linked immunosorbent assay (ELISA) and the confirmatory Western blot test. Both detect host antibodies to HIV and will measure the andtibodies produced if infected by HIV. ELISA is the initial screening test and has sensitivity and specificity 99% when done at 30 days. A false-negative ELISA result occurs most commonly when the test is performed in a newly infected patient before an antibody response has developed (the window period). As a routine protocol ELISA must be done at 90 days and then again at 6 months for complete confirmation and peace of mind. Please get tested again at 6 months from date of sex with prostitute.