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Doctor insights on: P24 Antigen Test Accuracy 20 Days

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Antigen (Definition)

Antigens are chemicals which upon exposure to the surface or inside of the body, will cause a reaction term allergic. Many substances will do this and allergic response is the basis for immunological protection for ...Read more


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Had protected vaginal sex with CSW. How reliable is negative HIV p24 antigen combo test at 20 days mark? Also, getting results tomorrow for HIV RNA PCR at 19 days. Will that be conclusive if negative?

Had protected vaginal sex with CSW. How reliable is negative HIV p24 antigen combo test at 20 days mark? Also, getting results tomorrow for HIV RNA PCR at 19 days. Will that be conclusive if negative?

Pretty reliable: Most people who turn positive would be positive at least borderline by day 14-20. There are uncommon cases of over 1 month to turn positive. NOte that the incidence of this is far lower than the liklihood of someone Totally Lying about What They are Doing! .
Oh, sorry, that's for the antibody. The antigen/other measures of virus should be done TOGETHER with antibody. REALLY low risk of false negat ...Read more

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Plz Doctor, Is P24 antigen ECL test negitive at possible exposure after 7 day accurate? After 28 days (today), there is no symptoms and all is normal.

HIV: Not necessarily. You should have both antibody testing again at 3 and possibly 6 months after exposure, and perhaps a PCR for HIV RNA at this time which although expensive may solve the question. ...Read more

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What is the accuracy of p24 antigen and antibody HIV testing 4-6 weeks post PEP testing? For something incredibly minor, would this be reliable?

What is the accuracy of p24 antigen and antibody HIV testing 4-6 weeks post PEP testing? For something incredibly minor, would this be reliable?

HIV nucleic acid: The antigen antibody combo tests are quite good. But you should repeat the test at three months. At three months, if you get a HIV nucleic acid test and that is negative, you will more sure of the result. ...Read more

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Hiv test antibody and p24 antigen (cmia) done after 5 months 15 days after possible exposure came out non reactive. Is this result satisfactory. Help?

Hiv test antibody and p24 antigen (cmia) done after 5 months 15 days after possible exposure came out non reactive. Is this result satisfactory. Help?

HIV?: Very low likelihood of HIV infection with those test results. Greater than 97% of people are positive by 3 months and virtually all are positive at 6 months. ...Read more

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How reliable negative result of p24 antigen and hiv antibody test at 45 days? Percent of people get accurate result on the said test by this period?

How reliable negative result of p24 antigen and hiv antibody test at 45 days? Percent of people get accurate result on the said test by this period?

No worries!: This combination of tests is 100% conclusive any time 4 weeks or more after the last possible exposure. Nobody with negative resutls at 45 days is later found to have HIV. So all is well; you can move on without worry. Best wishes and stay safe! ...Read more

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Took HIV Antibody 1&2 Test and P24 Antigen test 10 days after PEP. Results non-reactive. A bit early. All other blood panel metrics normal. Thoughts?

Took HIV Antibody 1&2 Test and P24 Antigen test 10 days after PEP. Results non-reactive. A bit early. All other blood panel metrics normal. Thoughts?

Not conclusive: These results are reassuring; it is unlikely you were infected. However, the results are not conclusive. Following PEP, it is necessary to test for HIV longer than otherwise, maybe up to 4 months. (PEP is great when needed, but it prolongs the time of uncertainty about whether infection occurred.) Discuss with the clinic or doctor who prescribed the PEP and follow his or her advice. ...Read more

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What kind of doctor provides the p24 antigen test?

What kind of doctor provides the p24 antigen test?

Any doctor: Any physician can order this test to be done in the lab, but infectious disease specialist (id) or primary care physician usually request this test. ...Read more

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I have not taken one yet, but how often does a p24 antigen test have a false positive result? And how accurate are they after 2 weeks?

Below: About 2-8 weeks after exposure, antibodies to HIV are produced in response to the infection and remain detectable in the blood thereafter, making the HIV antibody test useful for detecting infections

After two weeks, the accuracy is questionable

The p24 antigen test is one of the earlier tests developed to detect HIV infection. Because levels of p24 antigen fall as antibody develops and do not ...Read more

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How reliable is a p24 antigen HIV test a month after been exposed?

How reliable is a p24 antigen HIV test a month after been exposed?

Not widely used: The level of p24 antigen and the amount of virus (viral load) increase significantly soon after initial infection. It is during this time frame, before HIV antibody is produced, when the p24 test and the HIV antigen/antibody combination test are useful in helping to diagnose infection. About 2-8 weeks after exposure, antibodies to HIV are produced in response to the infection and remain detectable. ...Read more

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4th generation hiv test 13wks, 4days post possible hiv exposure, result=negative. No p24 antigen/antibody, could antibody develop at a later time?

Some times: To be safe, get a HIV nucleic acid test at 6 months after exposure.
Wish you good health! - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form.
Practice safe sex, if you have sex. ...Read more

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I had an sexual int. With an escort 7 months ago. I have last Anti Hiv 1/2+P24 Antigen test after after 7 month. My tests are negative. Am I free or not?

I had an sexual int. With an escort 7 months ago. I have last Anti Hiv 1/2+P24 Antigen test after after 7 month. My tests are negative. Am I free or not?

HIV: I know in the United States that the testing for occupational exposure has been initial 2, 4 and 6 months then no exposure assumed. If you are negative 7 months after exposure. You are negative and free. ...Read more

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I want to test for HIV which test will give accurate result. Its been 6 weeks now after exposure used condom. Had a p24 antigen on 20th day its negtve?

I want to test for HIV which test will give accurate result. Its been 6 weeks now after exposure used condom. Had a p24 antigen on 20th day its negtve?

HIV RNA Test: The best and most accurate test is the HIV RNA pcr test. But, you wore a condom. The test will be negative. As you have been taught over and over and over here. Please do the test and then get on with the rest of your life. ...Read more

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I had sex. Used condom. Took p24 antigen on 18 day mark its negative. Took HIV duo 1& 2 antibody 4th gen at 8 weeks its non reactive. Do I need more test?

I had sex. Used condom. Took p24 antigen on 18 day mark its negative. Took HIV duo 1& 2 antibody 4th gen at 8 weeks its non reactive. Do I need more test?

Stop worrying: You're very unlikely to get anything if you're wearing a condom, period. These tests are negative. The vast majority of men wouldn't even seek testing. Listen. You're 21 years old and you're a man now. I'm sorry that your (was it first?) experience of loving left you feeling like this. But you're not damaged / dirty either physically or spiritually by it. Talk with somebody wise -- maybe even dad. ...Read more

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Neg p24 antigen test and neg HIV1/2 antibody test at 11wks post exposure. Can I trust these blood tests and finally have some peace of mind? For HIV

Neg p24 antigen test and neg HIV1/2 antibody test at 11wks post exposure. Can I trust these blood tests and finally have some peace of mind? For HIV

You are fine: Please trust these results. I'm sorry you had a scare, but I hope that you will have confidence that you're not infected with HIV and that you will put this behind you. I also hope that you will treasure the memory of having shared love. Human love is never perfect and always involves risks. But I hope you'll find real joy with another person, and share safe intimacy when the time is right. ...Read more

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Is HIV P24 antigen detectable 17-19 days after PEP? I have read that generally speaking it is detectable at 14 to 16 days on average. Thoughts?

That's about right: P24 can often be detected as early as 10-12 days after infection. But these figures are pretty good on average. ...Read more

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I had protected sex with a sex worker a month ago I got loose motions for a week and I am afraid of HIV I did a p24 antigen at 20 day mark its negatve?

STDs: I am sorry you did not use a condom when you had your sexual encounter. But, loose stools are in no way any indication of HIV or any other std. Your HIV test was done too soon to be accurate or valid.

Remember there are twelve common stds. Five of them are potentially life threatening. Worrying just about HIV is really missing the gravity of the situation. ...Read more

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I had sex for 1st tym with a sex worker used condom symtom. Weakness had loose stool now ok. Had p24 antigen on 20 day mark its negative afraid of hiv?

I had sex for 1st tym with a sex worker used condom symtom. Weakness had loose stool now ok. Had p24 antigen on 20 day mark its negative afraid of hiv?

You used a condom: You used a condom. Your risk is only in your brain. You did not get hiv. I am going to be very frank. This is paranoia and guilt. There is no risk here for hiv. If I was your doctor I would do one more test in another month or two but would refuse any more tests. If there is a way you can get over your guilt then that would be the healthiest thing you can do. You do not have hiv. ...Read more

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I have been exposed to HIV my blood work detects I have p24 antigen. Does this mean I have or will get HIV? I only have one partner.

HIV: Please consult your physician to discuss all the issues. You will require further test like viral load and CD4 count to help confirming the disease and the need to start anti hiv meds. ...Read more

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Simultaneous detection of p24 antigen and antibody HIV 1and 2 cmia = 4th generation ag ab combo? Which means u have been tested for p24 /antibody?

Yes and no...: The antibody portion of the test detects antibody to several HIV antigens in addition to p24. Probably you do have antibody to p24, but the test doesn't distinguish these various types. And it doesn matter. If your test is negative and it has been 4 weeks or more after your last possible exposure to HIV, the result is conclusive. ...Read more

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Hello doctor I tested for p24 antigen combined antibody/antigen 9weeks after possible exposure and the results came to be negative should itrustresult?

Conclusive: The HIV antigen-antibody combination tests are 100% conclusive any time 4 weeks or more after exposure. Your results prove you did not catch HIV. You don't need any furtther testing. ...Read more

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Is it possible to have an HIV p24 antigen, HIV antibody, and HIV PCR accurate 5 weeks after exposure?

Is it possible to have an HIV p24 antigen, HIV antibody, and HIV PCR accurate 5 weeks after exposure?

Yes in part: The tests that detect actual HIV virus, such a the HIV viral load (pcr), will likely be positive 5 weeks after an exposure that results in transmission of hiv. The HIV antibody test may still be undetectable. So, if you are very worried about acute hiv, it is very important to discuss with your health provider so they do the right tests. ...Read more

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Low risk exposure. Tested with the p24 antigen on week 1, 3, 4 weeks and DNA hiv pcr at week 6 all negative.4 months elisa and negative. Conclusive?

Yes: Love safely from now on, and cherish the memory of what what happened, no matter how imperfect it may have been. You shared love and that is always wonderful. ...Read more

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Is it possible to hav all 3 - P24 antigen, HIV antibodies & HIV DNA undetectable at 4 MONTHS of risky exposure? Did 4th gen (Ab/Ag) & PCR DNA together

Is it possible to hav all 3 - P24 antigen, HIV antibodies & HIV DNA undetectable at 4 MONTHS of risky exposure? Did 4th gen (Ab/Ag) & PCR DNA together

Get over it, Bill: You are not infected. I'm glad. You need to find a way of getting these obsessive thoughts out of your head, for your sake and the sake of those who love you. Get on with your life, a better and more mature man for what you went through. ...Read more