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  • Test doubt

    I took a HIV test at 12 weeks post exposure. It was CMIA test - HIV1/2 and P24. I checked with the lab what machine do they use they said aBbott architect. I downloaded the manual and checked it checks for HIV 1 - Group M and O and HIV2. What if the infection is from another group of HIV1 like Group P or Group N? The test will then miss the infection ? Also the p24 will not be detectable at 12 weeks so the test will rely on on the antibody portion. Now if it can’t detect antibody of Group p and Group N then don’t you feel it’s not conclusive?

  • #2
    Pl clarify


    • #3
      Pl reply doctor


      • #4
        Thank you for your question. Group M is the most predominant subtype of HIV1. Groups O, N and P, and HIV 2 are very rare and mainly found only in Africa subcontinent. Most test kits have the ability to test Groups M, O and HIV 2, but with the advance in medical technology, they may well include Groups N and P in future.


        • #5
          Hi doctor,

          Based on the case above, if that person is infected with type N & P and undergo Ag/Ab test even on the 12 week it is not considered conclusive. Am I right?


          • #6
            If the Ag/Ab test does not test for groups N & P, then logically it will not be able to detect a person infected with groups N & P. It is however important to note that group M is the most common subtype and forms the vast majority of HIV 1.


            • #7
              Which test detected HIV group n and p? My test is concluded or not?


              • #8
                This is an interesting topic, and I have provided some links for you to have a read if you are interested.

       -> Researchers have done studies to assess if the current Antibody tests available are able to detect rarer subtypes. This article proves that the ARCHITECT HIV Combo Ag/Ab (HIV Combo) and RealTime HIV-1 (RT) assays were able to detect all subtypes including groups N and P.

       (page 455) -> This article summarizes data from other studies that have proven that both commercial tests and HIV 1 Western blot tests are able to detect groups N and P as well.

                It is possible that manufacturers do not include groups N and P in their package inserts until they receive approval by the respective country's health authorities. In short, I believe your test to be conclusive, if you have any further doubts about the test you underwent, I advise you to check with your doctor.
                Last edited by Dr. Edwin Ong; 06-13-2019, 10:22 PM.