Dear Doctor,

I had a Westernblot test at 73 days after a possible exposure and it came back negative. No bands were present. If I were seroconverting what bands would be present by 73 days? I had an Elisa test done 5 weeks later. My results were negative. I didn't ask if a Westernblot was done. Which bands on the Western blot are the first to show up and on average how soon do these bands appear after infection ?

Usually the screening process goes like this. If the ELISA is negative, no further testing is done. If equivocal, or positive, a western blot is done. In almost all cases the first band to show up is p24, followed quickly by gp120 or 160. These bands usually occur by 4 to 8 weeks after infection. It may take up to 5-6 months for all 8 bands to appear. But a western blot is considered positive usually if 2 or more bands are present from at least 2 different areas of the virus. MH