Late seroconversion

Originally Posted: 
Thursday, February 23, 2012




I had sex with a sex worker but I used condom. Some days later I noticed two little scrachtes at the base of my penis. I am concerned about the possibility of they were not covered by condom. So I tested PCR Quantitative For HIV 13 days later and it was ok. 43 days after this exposure I tested again (3rd generation HIV 1 & 2) and 59 days I tested again (4th generation test). They all were negative. But 5 days ago I had fever (38,5ºC) and yesterday again (39ºC). I have some problemes with Diarrheya too. These problemes began at 9 weeks after the risk situation and come again at 10 weeks after the risk situation. So I am afraid that it can be late seroconversion. What do you think? I'm scared.


The 4th generation test can find p24. But I tested 59 days after the risk situation. Is it reliable? Let's suppose I am positive, the test could find the p24 antigen if I had not developed yet the antibody for hiv?


Please, help me.



Hello and Thank You for Using the AIDS Vancouver Helpline as your source of HIV/AIDS related information.


First, it is great to hear that you used a condom during your encounter, as it is very rare to contract HIV from having protected sex. To transmit, the HIV virus needs direct access to the bloodstream through a mucus membrane, open cuts and sores (in theory though), the anus, the vagina or the urethra of the penis. Even if you did have scratches at the base of your penis that were not protected by the condom, it is important to note that the scratches would have to be actively bleeding to for you to be infected. However, this is theoretical because there has never been a reported case from a scenario such as that.


The window period for the 3rd generation test you took is 4 weeks-3months (95% of infections are detectable within 4-6 weeks), so the negative result you received at 43 days is a good indicator of your status.


In regards to the 4th generation test you took (which looks for both the antibodies and the p24 protein antigens), the window period is 4-12 weeks for the antibody portion of the test. Detection of the antigens (p24 protein) is only detectable immediately after infection and only for the first couple of weeks. The 4th generation test that you took at 59 days, that came back negative, is also a good indication of your status because as it was performed during the window period for the antibody portion of the test (as long as you have not had any risky exposures since then.)


Late seroconversion is very rare, but could happen. Therefore, for completely conclusive and definitive results, official HIV testing guidelines still recommend re-testing at 12 weeks (90 days) post exposure.


It is important to note that HIV symptoms mirror other viral infections, and can be due to a number of things. Therefore, testing is the only way you can know for sure if it is HIV, which you did!


Take care,



AIDS Vancouver Helpline Volunteer


Phone (Mon-Fri 9-4pm): (604) 696-4666



Submitted by Anonymous (not verified) on

Hello. I just got the results of my CBC. I'm afraid because it showed 10 % of atypical lymphocytes. It can be considered a sign that I am experiecing the seroconversion or it can be caused for some other reasons? I'm really worried and I got my results by internet, so I did not talk to the doctor yet.

Thank you

Helpline1's picture
Submitted by Helpline1 on



Hi there and thank you for using AIDS Vancouver as your source of HIV/AIDS information.

A Complete Blood Count test (CBC) examines the concentration of white blood cells, red blood cells, and platelets in the blood. Though CBC is one of the most commonly practiced blood tests, it is not suitable for HIV screening because that test does not look for either HIV-specific antibodies or P24 antigen (the antigen on HIV). Therefore, your CBC test results do not tell whether or not you are experiencing seroconversion and cannot be used to diagnose an infection.

The only way to identify an HIV infection is to receive a HIV test. The most common form of HIV testing is the 3rd Generation EIA, a test that looks for HIV-specific antibodies, available in Greater Vancouver. For more information about HIV testing sites in Vancouver, you can visit:

If you are curious about your HIV status after engaging in a high-risk activity (unprotected anal or vaginal sex), I do recommend you to visit a HIV testing site during or after a window period of 4-weeks to 3 months for an accurate result. The reason why I do not encourage you to go for a test before the window period is that your body might not be a detectable level of HIV-specific antibodies yet. On average it takes about 21-25 days to develop detectable antibodies.

If you have any other questions or concerns, please feel free to contact us again.

In Health,


AIDS Vancouver Helpline Volunteer


Phone (Mon-Fri 9-4pm): (604) 696-4666


Submitted by raj007 (not verified) on

respcted sir
pls see the attachment file
its my hiv rerpot its tke after 50 days
my report is HIV I & II Antibody + HIV 1 p24 Ag




1" is this report is relibal

i have some lokupalkia in mouth around 2 month

helpline2's picture
Submitted by helpline2 on

Hi again, 

While your negative result at 50 days is a good indicator of no current HIV infection, as stated previously, current international HIV testing guidelines suggest testing at or after 12 weeks (84 days) for conclusive results. As such, you may wish to opt for testing again at that point in time. In addtition, we do recommend that all sexually active individuals opt for regular  STI (including HIV) testing for their safety and the safety of their partners. Depending on the individuals this may entail testing annually, biannualy, or every 3-4 months. Additionally, leukoplakia is not specific sign of HIV infection, nor can other signs and symptoms be used to diagnose HIV infections. Testing is the only reliable way to diagnose an HIV infection, and as stated previously, your test results are a good indicator of no current HIV infection. 


AIDS Vancouver Helpline Volunteer

Phone: 604.696.4666 (Mon-Fri 0900-1600)

Submitted by Rez (not verified) on


Firstly, it is great to visit your website..very my question are:

I test P24 at weeks 11.5 (Not-Detected) it accurate enough??
also had rapid test at week 13 (Not-Reactive) it reliabe for me??

could you please explain a little bit further, what can cause the so called late seroconversion??

Helpline1's picture
Submitted by Helpline1 on

Hi Rez and thanks for using the AIDS Vancouver Online Helpline as a source for HIV/AIDS related information.

The P24 Test you received at 11.5 weeks is known as the 4th Generation EIA (or DUO/COMBO) Test.  The P24 antigen portion of the test is detectable immediately after infection (3-4 days post exposure) for the first 2-4 weeks. The antibody portion of this test is detectable from 3-4 weeks onward.  Many HIV Specialists consider this test conclusive at 6 weeks.

The Rapid (Point of Care/Tridot) Test you received at 13 weeks post exposure is definitely conclusive and no further testing is required.

Late seroconversion is very uncommon and is usually because of one of the following three reasons:

  1. Being treated by some types of chemotherapy,
  2. Being treated for Hepatitis C, and,
  3. Have an existing immunodeficiency disease.

I trust I have addressed your concerns however, should you require further information, feel free to contact us again.

In good health,
AIDS Vancouver Helpline Volunteer

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The AIDS Vancouver Helpline is a volunteer-driven information, referral and support service related to HIV and sexual health. Volunteers are trained in active listening, HIV and sexual health information, and local resources and services. Volunteers are not doctors, nurses, or other licensed professionals. Volunteers do not give advice, and strive to provide service-users with adequate information and appropriate referrals.

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