HIV test result !?

I did an HIV test today. It came back non-reactive. But I am worried coz the test report showed that an s/co ratio was 0.10. It was non reactive since it was less than 1. But what does the number 0.10 mean?  Do I have HIV?

1 Answer

  • 9 months ago
    Favorite Answer

    The antibody test for HIV antibodies is a composite test in which we call ELISA. That name is descriptive of the test that incorporates the use of antigens to detect the corresponding antibodies but has a chemical color component used as a detector. It is a color development system that involves degrees of color. Some color can be solely background color development because of the nature of the chemicals used and stability issues. 

    The S/CO is the signal to cutoff ratio. It is a ratio that is used to see if the color generated is only background noise or if it is significant enough to exceed the 1.0 cutoff. In essence it is the strength of the reaction that is taking place. In comparison a person who has an S/CO ration of 55 has a 100% positive predictive value for being a true positive. A S/CO of 0.1 is simply background color nowhere close to 1 and nowhere close to what most positive people have. 

    The S/CO ratio gives the doctor an indication of how strong the reaction is and predictive of true positives. Low values that are borderline around the 1 value are termed weak positives and most false positive results are in this borderline range. Normally there is a delay in confirmatory testing which as stated gives the doctor a heads up on how positive the result is. 

    The present testing protocols calls for antigen and antibody testing which can detect HIV early than just relying on antibody testing. The combo test is the preferred test as the antigen markers show earlier than the antibodies do for HIV. Early infection is associated with a greater risk of spreading it because the amount of virus during the acute infection is very high thus the combo test can help stop the spread of HIV infection better than just antibody testing. 


    You stated that it was 0.1 and non-reactive. A non-reactive means negative. Your HIV was negative for the antibody. The 0.1 is simply background color. 

Still have questions? Get your answers by asking now.