Different HIV Tests – When to get tested for confirmed results?

“Out of 10 questions I get from my patients and the visitors of my website, 4 are related to catching a sexually transmitted infection because they had oral or protected or unprotected sex with an unfamiliar person” says Dr. Karthik Gunasekaran, one of Chennai’s popular sexually transmitted infection specialist at Metromale Clinic & Fertility Center, Chennai.

“No exceptions, everyone does gets involved without thinking twice and only after reaching orgasm, do they realize and start to think if they could have caught HIV, HPV or any other STI but wouldn’t that be too late?  The answer is Yes and No”, adds Dr. Karthik. In this article, let’s talk about different HIV tests that are available currently, when to get tested for confirmed results and what does your report results mean.

What happens after having unprotected sex with a possibly infected person?

The most feared disease of STDs is HIV/AIDS. Though there are other diseases such as HPV, Syphilis caused by virus, many (rather most) are worried about contracting HIV. Some don’t even know that certain bacterial infections such as Chlamydia, Gonorrhea are most commonly spread STDs.

If you have unprotected sex with a possibly infected person (whether a male or a female), you may or may not contract the virus in one interaction. Chances are very small but certainly not zero. If you get infected, the virus enters your blood stream and starts multiplying very rapidly. During this period, you won’t have any symptom. This multiplication period can be 5 to 14 days long until the first symptom shows up. This is called a ‘window period’. If you happen to have unprotected sex during this window period with another healthy individual, you will be very well transmitting the virus to the healthy person. The window period is the biggest disadvantage in people who contract the virus because, if the first symptom showed up in less than 72 hours after contracting the virus, you would have a chance of undergoing ‘Post Exposure Prophylaxis (PEP)’ treatment that can prevent you from becoming a HIV patient.

Common initial symptoms of HIV are:

1. Fever
2. Rash
3. Flu like symptoms
4. Headache
5. Muscle aches
6. Swollen lymph nodes etc.

When you present yourself with any of these symptoms with a recent history of having unprotected sex, your doctor would advise you to get tested for the full set of Sexually Transmitted Infections, instead of just HIV. Reason being, there can be several other diseases that can get transmitted and some may be treatable with medicines.

Is there a vaccine for HIV?

As of now, no. Researchers are still working on it and they are sure to come up with a vaccine at least for the dominant variants in the coming decade. Read more on ‘HIV Vaccine’.

Types of tests to detect HIV infection

There are mainly 3 types of tests to detect HIV infection in a body:

1. NAT – Nucleic Acid Test. 
2. Antigen/Antibody Test
3. Antibody Test

NAT – Nucleic Acid Test

NAT test looks for the presence of the actual virus. Doctors often call it ‘viral load’. This is a relatively expensive test. Real Time Polymerase Chain Reaction (RT –  PCR) is one method of detecting HIV RNA and is performed using qualitative Nucleic Acid Amplification assay. The test amplifies and detects HIV 1 RNA and pro-viral DNA in plasma and in anti-coagulated blood.

In order to perform NAT, blood is collected from the vein of the person and sent to the lab for results. It usually takes a day or two for the results to come out.

NAT is performed on people who had a very recent exposure to the virus and are showing symptoms of HIV. The test is recommended if it has been around 10 days since possible infection.

Antigen/Antibody Test

After HIV enters the human body, it produces an antigen called p24. It (p24) is a structural protein that makes up most of the virus. During the window period, the levels of p24 are very high. Detection of p24 antigens can be done from 11th to 30 days after exposure. During this time, the infected body may or may not have produced any antibodies.

After the virus produces p24 antigens, and when the body becomes aware of the invasion of a harmful microbe, it starts producing antibodies to combat the virus. If it has been over 30 days after exposure, your doctor may suggest you to go for an antibody test to confirm the infection. Most of the time, a positive antibody test is good enough to confirm the infection. To remove any doubts of false positives, you may go for an antibody test again after a couple of weeks past the first test. Blood is usually drawn from the vein or in some cases, a finger prick may just suffice.

Antibody Test

Antibodies can be detected in the body (most often) after 30 days after exposure. Antibodies can be detected either from the blood sample or oral fluids taken from the buccal area or from the gums. Self test kits to detect HIV are available but it is best to get tested from an authorized HIV testing lab near you to avoid false positives.

Important things to keep in mind if you think you will ever have unprotected sex with someone

1. Stop googling and don’t wait for a symptom.
2. Don’t assume that your partner is safe and you wouldn’t have contracted any infection.
3. Do NOT trust your stranger’s words when he/she says that he/she never had any symptom. He/she may be telling the truth but not everyone will see symptoms after getting infected.
4. Don’t delay in seeing a good sexologist near you.
5. Get all the tests requested by your doctor immediately.
6. If your doctor advises you to go on Post Exposure Prophylaxis treatment, you MUST go ahead without any hesitation. After all, it’s the last 72 hours of precious time you will have in your hands to save yourself.

Post Exposure Prophylaxis (PEP)

If you think you had potential exposure to HIV, the first thing you need to do is – do not panic. Just go to your nearest andrologist or sexologist or even a general physician and explain to him/her what has happened. You will then be put on PEP – Post Exposure Prophylaxis, if the exposure was less than 72 hours ago. This can prevent HIV from taking control of your body. Read more on PEP for HIV.