Hello.

Thanks for your query.

Regarding your first query, that is risk of HIV infection after an unprotected sex with a woman you do not know, is high.

Now, let me first tell you that we essentially have two types of test for HIV-(1) screening and (2) diagnostic. As a stepwise approach, we go first for a screening test as they are highly sensitive, and if positive, we go for a diagnostic test which is highly specific.

The screening test is ELISA (Enzyme Linked Immunosorbant Assay) test. It is a serological test that depends on antigen antibody reaction. If ELISA is positive, we can either confirm the HIV infection with a triple ELISA or western blot and can additionally get HIV RNA.

If ELISA is negative, but there is a strong positive history, then we should repeat ELISA after the window period (disease is proliferating but load is not enough for the test to come positive), which is usually 3-6 months.

If repeat is negative, to be sure there is no infection, repeat it after 1 year, and if it is still negative, one is unlikely to be infected.

After ELISA is positive, sometimes western blot and HIV RNA are either negative or else indeterminate. Then it should be repeated after 6 weeks again. If this (repeat) is negative still or there is no progression, HIV 1 infection is unlikely.

Regarding HIV RNA (PCR RNA - Polymerase Chain Reaction Ribo Nucleic Acid) I shall like to caution you that this test is extremely sensitive, sometimes a false positive result may come (you do not have infection and you are test positive). It can be psychologically devastating. Also, HIV RNA test is more useful in a diagnosed case of HIV to decide when to start anti HIV drugs.

So I shall suggest you to get an ELISA test done now, and if it is negative repeat it after 3-6 months. If any of these is positive, confirm it with triple ELISA/ western blot whichever is available.


Hope I have answered your query, I will be available to answer your follow up queries.

Regards.

---

Dear XXXXXXX
Welcome back.

Although in your initial question the words were mixed, but it made a sense. The basic fact is there is a sense of insecurity in your mind as there has been a possible exposure and this will not go away by any kind of counselling or reassurance and you cannot take rest till it is confirmed that you are HIV free.

Certainly 9-10 days post exposure is too early and you have to go for a repeat test which is most appropriate at this point of time. As you cannot wait further, the 4th generation test, that is P24 combo/duo test is very appropriate at this point of time.

At 30 days post exposure, the test has a very high sensitivity to detect HIV and if this comes negative now, be reassured. Literature supports that there is 98% chance that you do not have infection if the Duo test has come negative at 30 days post exposure. So go for this test and clear the doubts.

I am available for a followup if you still have any query.

Regards

---

Hi,

Thanks for writing back.

If you have facility for P24 duo test, it is more senitive as it looks for both antigen and antibodies.

However, if there is no facility for this test, you should repeat PCR RNA test at this stage as the credibility of the test improves with time since more and more copies of the virus is produced with time (that is antigen load increases) and if the test is still negative, you are reassured.

Your doctor is right that a PCR RNA test is sensitive enough to pickup HIV antigen as early as seven days but if the result of the test is negative at 7-10 days, then it is not correct to reassure that you do not have HIV infection, and to be sure, the test MUST be repeated after 4 weeks again. If it is still negative, then relax.

Regarding percentage credibility, again 97-98% chance (a reasonably high chance to reassure you) is there that if PCR RNA at 30 days is negative, you do not have infection. In the given circumstances, if this test comes negative again, I will say you do not have infection.

Take care, relax.

---