Common "P24 Antigen" queries answered by top doctors | iCliniq

P24 Antigen

P24 is a capsid structural protein that makes a protein shell on the surface of the HIV (human immunodeficiency virus). It helps in identifying the actual HIV particles present in the blood. They show a positive result when the test is taken after two to three weeks of HIV infection. P24 protein cannot be detected after a week of HIV infection as the virus takes some time to get multiplied. It is again undetectable when sufficient antibodies to HIV are produced. At this point, the standard HIV antibody test shows a positive result. Later in the course of HIV, it becomes detectable.

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Are the results of Elisa test for HIV screening reliable?

Query: Hello doctor, I have been tested for(Human Immunodeficiency Virus) HIV 1 and 2 many times. My tests are 10 weeks card test negative. 12 weeks Elisa (Enzyme Linked Immunosorbent Assay) serum test negative. 14 weeks Elisa serum and p24 test negative. 16 weeks Elisa serum test negative. 23 weeks Elisa ...  Read Full »

Dr. Sushil Kakkar

Answer: Hello, Welcome to I understood your concern and I have viewed the images. (attachment removed to protect patient identity). Your HIV(Human Immunodeficiency Virus) screening tests are conclusive. A screening test at and after three months mark from risk exposure is considered final and c...  Read Full »

After 2 months of HIV tests, I have no symptoms. Am I safe?

Query: Hello doctor, I have had HIV (Human Immunodeficiency Virus) 1 and 2 antibody test to detect antigens p24, Glycoprotein (Gp41, and Gp120) of HIV immunochromatography after 28 days of unprotected vaginal sex, and the results are nonreactive. Does it mean I am safe from the virus? I am now two months p...  Read Full »

Dr. Sushil Kakkar

Answer: Hello, Welcome to This HIV (human immunodeficiency virus) screening test involves antibodies and antigens accurately. It detects the majority of those infected at four weeks, whereas its sensitivity increases between 99 and 99.9 % at six weeks. So most HIV specialists consider the resul...  Read Full »

Can unprotected sex cause HIV? Please advise.

Query: Hello doctor, I had unprotected sex with my neighbor. I am really afraid of HIV. Please help me.  Read Full »

Dr. Ashok Kumar

Answer: Hello, Welcome to I read your query and understand your concerns. Please scan your reports and attach it while posting the follow-up query.   Read Full »

Which tests should I choose for STIs and HIV to be certain?

Query: Hi doctor, I had protected sex with a CSW (Commercial Sex Worker) five months before. I do not know the condom's status, either broken or ruptured. I was drunk that day, but I did not even ejaculate. Since I had a doubt, I took a test in the 4th week, HIV 1 and 2 antibody rapid tests from the labora...  Read Full »

Dr. Asmeet Kaur Sawhney

Answer: Hi, Welcome to I can understand your concern. You have gone for antibody testing for HIV (Human Immuno deficiency Virus) 1 and 2 many times, and it has come negative. When two tests for antibody detection based on different principles are negative, it means the individual is not having ...  Read Full »

Can p24 antigen test detect HIV early?

Query: Hi doctor, Before 19 days, I had protected sex with a part-time sex worker and freaked out after the incident. I am worried about any possible infection that could happen. I did a p24 antigen test. The results are p24 antigen on fourth day-0.125, sixth day-0.254, ninth day-0.271, twelfth day-0.274, ...  Read Full »

Dr. Ramchandra Lamba

Answer: Hi, Welcome to Yes, the titer of p24 is increased, but still, it is below the threshold value of being positive. Also, your PCR RNA done after two weeks is also negative. Your HIV 1 and HIV 2 tests done on the nineteenth day is also negative. It indicates that you do not have any inf...  Read Full »

I took the HIV combo test on the 32nd day after exposure. Is it a fourth-generation test?

Query: Hi doctor, I took the (Human Immunodeficiency Virus) HIV-1, HIV-2, and p24 tests on the 32nd day after exposure. I am attaching the file. I want to know whether this is a fourth generation test. If yes, what are the chances that a fourth-generation test is negative on the 32nd day and will turn posi...  Read Full »

Dr. Ravinder K. Sachdeva

Answer: Hi, Welcome to The answers to your queries are: The test which has been performed is a fourth-generation test. This test looks for HIV (human immunodeficiency virus) antigens and antibodies. The test result (attachment removed to protect the patient's identity) is negative. If this resu...  Read Full »

Why do I have a lot of bleeding after gay encounters?

Query: Hello doctor,I am a 32-year-old man. I had gay encounters with three men in a massage parlor on three different days. In all three cases, we have used condoms. In my second and third encounters, I got a lot of blood, and that too very dark-colored blood, and something else also came. I had a word wi...  Read Full »

Dr. Ashok Kumar

Answer: Hello, Welcome to I read your query and understand your concerns. First of all, I like to inform you that the transmission of HIV (human immunodeficiency virus) requires the mixing of body fluids. The use of condoms effectively prevents such mixing. I understand that there was bleedi...  Read Full »

Will I get HIV after unsafe sex even if a test is negative?

Query: Hello doctor, I had intercourse with a girl two months back without safety measures. After one month I took a PCR test and it got negative. After 40 days I took a test for the p24 antigen and it got negative. Then after 56 days again, I took a PCR test and it was negative. My symptoms started with d...  Read Full »

Dr. Basti Bharatesh Devendra

Answer: Hello, Welcome to Thank you for your query. The chances of transmission of HIV by single unprotected intercourse are low. The HIV antibodies and PCR tests are negative. The chances of HIV tests becoming positive later is almost nil. But it is better to go for an HIV antibodies test a...  Read Full »

Negative HIV test after oral sex with sex worker. Need help?

Query: Hi doctor, I am a 29-year-old male who got an unprotected blowjob from a sex worker at a massage parlor. I do not know her HIV (human immunodeficiency virus) status, I did oral sex only one time and I did not ejaculate in her mouth. Then she cleaned all with a towel and I washed my penis with soap ...  Read Full »

Dr. Basti Bharatesh Devendra

Answer: Hi, Welcome to The chances of transmission of HIV (human immunodeficiency virus) by single unprotected oral sex is almost nil unless there are bleeding wounds in the oral cavity. If the person is HIV-negative then there is no chance of transmission of HIV. The HIV antibodies negative te...  Read Full »

What does it mean if one is HIV positive yet antibody negative?

Query: Hello doctor, If you have an HIV test done and it is reactive but the antibodies test is negative, what does this mean?  Read Full »

Dr. Lohit Chauhan

Answer: Hello, Welcome to It might be due to the HIV test detecting the HIV antigen (p24), and the antibody test might still be in the window period (meaning, the antibodies against HIV have not been formed in the body yet). In any infection, the infection produces its antigen, and later when...  Read Full »

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