[Question #81] Dear Dr HHH

39 months ago
Dear Dr HHH,

I've seen your replies at Medhelp, I know you dislike questioning over conclusive results and repetitive questions. Ill write my situation simple, and list my queries in point form, I hope that is to your liking.

Long story short, unprotected insertive vaginal, duration 5 mins or so, with a csw from China. I am based in Singapore.

I took 3 tests, all of them are RAPID FINGERPRICK, results in 20 minutes:

Day 34: SD Bioline Ag/Ab Combo NEGATIVE
Day 40: SD Bioline HIV 1/2 Antibody NEGATIVE
Day 41: SD Bioline Ag/Ab Combo NEGATIVE

Now that we got the story figured out, here are my questions.

1) In Singapore, as with other official guidelines, they recommend 3 months as a conclusive test, therefore whoever you ask no doctor will tell you any earlier conclusive dates. I have read your replies at Medhelp, and you state that DUO tests (i.e 4th gen) are conclusive at day 28. Seeing that I took the RAPID 4th gen tests, would it be conclusive and why? Won't there be a chance for false negatives (I am aware of false positives that may happen from time to time)? 

2) That one exposure with the csw was my and last sexual exposure in my life. In terms of percentage, adding on to my rapid tests, how conclusive are my results?

3) I recently had a girlfriend, and I came clean to her about this matter. She is still a virgin, but I did perform cuninlingus on her on multiple occasions. What are chances of HIV transmitting assuming I was positive? I heard saliva isn't really a path to transmit HIV, however no sound advise online yet.

4) I have read that the rapid tests may produce a false negative as there may be a time the body does not have enough antigens AND antibodies for the test to pick up. Which will result in a false negative. Is this some myth or its really likely to happen? I took the rapid duo test close to the 5th and 6th weeks. I wish to also know the science behind it.

5) Just how reliable is a 4th gen rapid test is compared to the lab tests? All along I have been taking rapid tests, which is to be honest very difficult to find information about its reliability online, too many different statements AND the timelines ranged from 2007-2013, if you were to ask me, very unreliable information to rely on.

6) I hope you are familiar or aware about the brand of the test I took. I understand that people in the states uses alere or oraquick  but in Singapore the more popular choice for 4th gen rapid tests is SD Bioline. Is this brand reliable and conclusive at 28 days considering its a rapid fingerprick?

I fully understand my chance on a one off exposure was low, but I would wish to know about my status definitely on the basis on science and not by percentage, which I myself am fully aware of is honestly very low. 

I have also read many many Medhelp posts from you, I would choose to pay and ask you here because I would assume some posts and statements back in 2013 or more would have changed as we advance into 2015.

The main purpose is to know to what extent I can trust rapid 4th gen tests at this era, as I really cant perceive much from old medhelp posts regarding this and ever since you left the committee have been bound to insisting on a 12 week conclusive window period as well.

I hope you understand that I wish to responsibly start a monogamous relationship and for that to happen I would need to put this behind me. I really do appreciate your help, please advise me with your vast knowledge regarding the science of HIV. 

Regards,
WC
Edward W. Hook M.D.
Edward W. Hook M.D.
39 months ago

Welcome to a Forum.  As one how has read replies posted at our prior site on MedHelp, I am confident that it will not surprise you that I rather than Dr. Handsfield will be answering your question.  Just as on our prior site, we answer questions interchangeably according to our availability.  In addition, you will know that when I tell you that the likely that you acquired HIV from the single exposure you describe is essentially zero, you will no that people do get hit by lightning and there was even a person who was once struck by a meteor but that still does not mean you have any reason to worry.

The likelihood that your partner had HIV is low, the risk for infection from a single unprotected exposure is less than 1 in 1000, and your HIV tests (all three of them) are completely reliable.  The SD Bioline rapid test is well studied and as reliable as 4th generation tests performed in the laboratory.  You should believe your test results and  work to move forward without concerns for your health or the health of your partner related to the exposure you describe. 

I hope these comments are helpful.  Take care.  EWH

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39 months ago
Dear Dr Hook,

Yes, I was expecting either of you to reply :)

I am glad to know that all 3 tests done are reliable. However, are they CONCLUSIVE at the periods I have taken the test? That is to say I don't require a confirmatory 12th week test again?

I thought the SD Bioline was not familiar with you as I have never seen forums about it, I am glad you personally verified its reliabilty to be as accurate as lab tests.

Assuming there's a chance that I am one of those who only develop antibodies at the 3rd month (i know people with chemo or drastic health issues may take up to 6 months, I have no idea in general what kind of person may take up to 3 months. Maybe someone with stronger immune system?), am I right to say that the 4th gen rapid test would still be accurate as they will detect the antigen? Since no antibodies were formed to resist, my smart assumption is that the antigen aspect will be very detectable by the rapid test. Am I right to say that?

Ultimately, would my current results from the 3 rapid tests be conclusive or just reliable? I wish to affirm if there is a need for a confirmatory 12th week test or if I should go for 4th gen lab tests to further confirm my status. I will fully adhere to your advise if you say that the 3 tests I have done at day 34,40,41 is conclusive and no further testing is needed.

The main issue is, are 4th gen rapid tests conclusive at 28 days onwards as well? That is something I am always curious about because back in Medhelp days 4th gen rapids were unheard of and you and Dr HHH has only ascertained 4th gen lab tests.

Thank you Dr Hook!

Regards,
WC
Edward W. Hook M.D.
Edward W. Hook M.D.
39 months ago

Yes, your results are conclusive. No need for further testing.

The SD Bioline is used more outside of North America than here in the U.S.  As I said however, it still provides reliable results.  Please believe them.  When 4th generation tests become positive, they remain so from the time they become positive onward.  Their ability to detect infections earlier is due to the fact that they detect HIV antigen, which appears before antibody.  The antigen may disappear later as antibodies are made but once the test is positive, it will stay positive from that time forward in infected persons.  There is no need for further testing-believe your results.  EWH

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39 months ago
Dear Dr Hook,

Thank you, as an expert in the field, I will take your words with absolute trust that I require no further testing albeit the 12 week guideline imposed.

Just one more question to clarify and you may close the thread. For 4th generation RAPID tests, once an individual has exceeded the 28 days window period, is there any scientific possibility that the test will be unable to detect both antigens and antibodies due to both coincidentally having undetectable levels? i.e the time of testing is when seroconversion starts and p24 is being eliminated by rising levels of antibodies, however not detectable yet?


Also, for rapid fingerpricks, they only use a few drops of blood. The whole body has litres of blood present. I have always wondered why nobody has ever asked about the possibility that maybe the 5 drips of blood used for rapid tests may not contain the virus or have detectable levels of ag/ab since blood is always flowing and maybe the drips of blood missed it. Just a curiosity.


I have fully accepted your conclusion about my status and I will accept it, this is just a general inquiry. I've only dabbled a little in physics before I went to major in the arts, hence my knowledge of biology far evades me.


I take this time to thank you for your insight and assurance that I am indeed conclusively negative. I am now able to take my monogamous relationship into a step further, i.e unprotected sex with my partner. Thank you so much sir.
39 months ago
Dear Dr Hook,

Seeing that the last reply was not answered yet, please allow me to use a final posting to verify my query. Firstly I would like you to know that I really intend to go into a monogamous relationship and I personally wish to be 100% sure I do not have HIV, so as to not implicate my other half.

I fully realise the risk of the CSW having HIV in the first place, as well as my risk of contracting it at a first time exposure. However, do allow me to ask my questions for a peace of mind albeit the low risk of my exposure.

Firstly, having taken only rapid tests, I would like to know other than the window period which Ab/Ag is insufficient to detect, seeing that I have passed the window period before taking the tests, are there ANY ways for the test to not pick up the antigen or antibody?

Next, I can tell you that every other person who is afraid of the HIV virus has one fear in mind. "Why is my test conclusive at 4/6 weeks when CDC guidelines states 12? I'd better get tested at 12 again.", Scientifically speaking, how rare do antibodies take up to 3 months to be detectable? Also, if there exists a person where their system supressed the virus to not form antibodies until 3 months, would p24 antigen levels be very very high seeing that no antibodies were formed against it? That is to say even if someone is rare enough to take 3 months to start showing detectable antibodies, 4 weeks would suffice as the antigen is detectable in high levels and the 4th gen rapid test would still be able to pick it up?

What makes the rapid test fullproof at 4/6 weeks that it would deem conclusive? How safe am I to really say that I am 100% free from HIV?

I would love to listen to any scientific reasoning that shows that I am fully conclusively HIV negative.

My girlfriend is a very nice lady and I definitely do not wish to pass her a disease that will affect her life. As such, please do provide me with the science I need to tell myself I am ready to start a new relationship.

I really thank you from the bottom of my heart.
Edward W. Hook M.D.
Edward W. Hook M.D.
39 months ago

Your questions are redundant and were answered earlier.  To repeat-

I would like to know other than the window period which Ab/Ag is insufficient to detect, seeing that I have passed the window period before taking the tests, are there ANY ways for the test to not pick up the antigen or antibody?  You have passed the "window period" and if you had HIV, your test would be positive. This was said above.


"Why is my test conclusive at 4/6 weeks when CDC guidelines states 12? I'd better get tested at 12 again.", Scientifically speaking, how rare do antibodies take up to 3 months to be detectable? Also, if there exists a person where their system supressed the virus to not form antibodies until 3 months, would p24 antigen levels be very very high seeing that no antibodies were formed against it? That is to say even if someone is rare enough to take 3 months to start showing detectable antibodies, 4 weeks would suffice as the antigen is detectable in high levels and the 4th gen rapid test would still be able to pick it up.  I did not answer this early but it has been answered many times before. the CDC recommendations are overly conservative and have been given in their mistaken belief that they are better to be overly conservative than accurate.  This is the problem with recommendations from agencies whom, for political reasons, do not feel they can "afford" to be wrong.  If a persons were infected and antibodies were not present, the p24 antigen would be present and readily detected by 4th generations tests.  p24 antigen is typically detectable 2 weeks after acquisition of infection.


Rapid tests are well studied in many well conducted scientific studies.  The results should be believed!


Your fears are groundless. Your tests show that you do not have HIV.  You need to believe your results and move on.  EWH

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39 months ago
Dear Dr Hook,

Thank you for your clarification over CDC guidelines. I trust that the tests I took are indeed conclusive and I may proceed with a monogamous relationship with no fear of infecting my girlfriend. I will not go for a confirmatory 12th week test since you are confident that I am conclusively 100% HIV Negative.