Q: I am a 48 years male living in Indonesia for the last 15 years. I am in lowest risk of contracting group as I never had sex outside, never had any type of drugs, never had blood transfusion, and am very careful while having any injection or giving blood for tests. Recently, I had a routine HIV test for applying an insurance policy. The results shocked me and summary is cited below:

1. First test of HIV anti-bodies that was done three months back - Method: MEIA, Result: Reactive (s/co ratio 5.85)
2. Follow up test number 2 on same blood sample - Method: Immunochromatography assay, Result: Non-reactive
3. Third follow up test on same blood sample - Method: ELFA, Result: Non-reactive
4. Fourth confirmation test on new blood sample done a month back - Method: Western Blot, Result: Positive
5. HIV anti body test on my wife done last month - Method: MEIA, Result: Non Reactive
6. CD4 test on my new Blood sample done last month - Results: CD4 Absolute: 663 cells/l CD4 %: 35%
7. HIV-1 RNA (by RT-PCR method using Cobas Amplicor HIV-1 Monitor TM test, version 1.5 (Roche) done last month - Result: Virus Undetected.

I am utterly confused. During last three years, I twice had anti-viral medicines, once when I had a short bout of Herpes Zoster and the other time two years back, when I had Viral fever. At the age of 26 years, I had pleural effusion and was on medicine for about two years. Other than these, I never had any illness. Am I really HIV positive? If yes then possibly for how long I am infected? How could have I caught this virus? Why my wife did not get this infection when I am having regular unprotected sexual relation with her? What should I do now? Should I trust these test results?

A:I must confess that your history puzzles me. False positive test reports are not uncommon and normally even one negative test is taken as proof that the person is not infected. In other words, a positive test report should be ignored if any subsequent or repeat test is negative. The CD4 count also does not help in a diagnosis as it only represents how many are present per cubic millimetre of blood. Normal values in non-HIV positive persons generally range from 400 to 1200. Your report is in the normal range but does not rule out HIV. It is also true that the Western Blot test can be false positive for HIV due to cross-reactions with other conditions. I have also noted a slight ambiguity in your history. In the beginning you say that you have never had sex outside and at the end you talk of last one year. Over all, presuming you have had the tests done at an approved quality test laboratory, I feel the likelihood is that you are not HIV positive.