Testing Locations » California » San Francisco CA » Quest Diagnostics – San Francisco 490 Post Street – Employer Drug Testing Not Offered Quest Diagnostics – San Francisco 490 Post Street – Employer Drug Testing Not Offered Quest Diagnostics – San Francisco 490 Post Street – Employer Drug Testing Not Offered490 Post StSte 914San Francisco, CA 94102-1410 United States 490 Post Medical Buildingrn