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Looking for the percentages
An_246718 posted:
I had a possible exposure thru genital rubbing (definitely no penetration) with a women I did not know and can no longer reach.. I have taken a HIV 1/2 antibody and HIV DNA test on both day 16 and day 26, both tests were negative. I have also had a finger stick test on day 38 that was also negative.

I am a nervous wreck and am in need of some advice. I developed a sore throat and slightly swollen lymph nodes with NO fever on day 23. This sore throat is still on going today is day 36. My anxiety is causing me to see ARS symptoms everywhere.

My question is does anyone know the positive detection rate of the above three tests given the dates? I am going to test thru 3months for sure but the stress is deeply affecting me and three months or more of waiting is too much.
georgiagail responded:
What you engaged in was frottage (rubbing together of genitals). This activity is not assumed to be a risk of HIV transmission (assuming your partner was HIV positive).

The estimated accuracy of an HIV screening test at 25 days after a possible exposure is 95 percent; that is, 95 percent of newly infected folks will have enough antibodies present to be picked up by current testing methods.

By 90 days this has increased to 99.9 percent (the very very small percentage of folks who would need to wait until 6 months for the final tests would be those whose immune systems have already been severely damaged by other, very serious medical issues). The 36 day test would fall somewhere inbetween those percentages.

It would be highly, highly unusual that someone would test negative at 25 days and then positive at 90 days.

NervousinUtah replied to georgiagail's response:
Thank you Gail that is very reassuring, i was handling the stress caused by the uncertainity until I got a sore throat after that everything started to spiral out of control.

Just as a follow up what have you heard about the accuracy of the HIV DNA test that were taken thru stdexpress. From what you said of the antibody test results they at most only by you a couple of weeks at most. How reliable are they? at 2 weeks and 4 weeks?

Thank you for the info
georgiagail replied to NervousinUtah's response:
Testing that checks for material of HIV itself (rather than antibodies or antigens) are known as PCR tests (Polymerase Chain Reaction).

The overall process of extracting and amplifying the genetic material of an organism (in this case HIV) and then testing for it with a PCR test is called Nucleic-acid Amplification Testing or NAT. NAT tests generally take two forms: DNA PCR tests and RNA PCR tests.

RNA PCR tests are most frequently used for screening blood donations and donor organs for HIV, while DNA PCR tests are used for testing newborn babies born to HIV positive mothers.

Both types of test can be used to measure the amount of virus that is present within a person's body (when they will usually be referred to as 'viral load' tests). NAT is sometimes also offered for diagnosing individuals, but because it is costly and complicated to perform, antibody testing is far more common in testing clinics.

NAT generally gives positive results much sooner than standard antibody testing would, making it useful in situations where early diagnosis is necessary.

A DNA PCR test will provide positive results within three to four weeks (sometimes sooner). As long as the recommended amount of time has elapsed before taking the test (people taking the test for personal diagnosis should ask their testing clinic if they are unsure), the test will be able to give a very accurate result.

The downside of this more expensive testing is that false positive results are more common than false negatives due to the PCR test's sensitivity, so all positive results must be double checked using a standard antibody test.


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