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Tested negative for DNA PCR and antibody Elisa test. How accurate is it?

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General & Family Physician
Practicing since : 2001
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How accurate is the DNA PCR HIV test at 30 days or more of exposure. On the 32nd days of my exposure I tested negative with DNA PCR and Antibody Elisa test? Is this an accurate test?
Posted Thu, 24 Oct 2013 in HIV and AIDS
Answered by Dr. Michelle Gibson James 1 hour later
Brief Answer:
it would be accurate

Detailed Answer:
HI, thanks for using healthcare magic

Different HIV tests have different window periods. The window period is the time it takes for a test to be able to definitively detect ,with minimal error, whether a disease is present.

The DNA PCR test looks for the HIV virus itself.In this way it differs from the ELISA test which looks for antibodies in the blood, these are formed when the body reacts to the virus and may take a long time to form in some persons.

Because the DNA PCR test looks for the virus itself and not the reaction to it, the window period is only 2 to 3 weeks (14 to 21 days).
This means that if this test is done after this time , it can determine conclusively whether a person has HIV or not.

If your DNA PCR test was negative after 30 days that means that you definitely do NOT have HIV.

With the ELISA, the window period is 3 to 6 months.

I hope this help, feel free to ask any other questions
Above answer was peer-reviewed by
Follow-up: Tested negative for DNA PCR and antibody Elisa test. How accurate is it? 27 minutes later
Hello, Thank you to take the time to answer my questions so fully. I would like to ask a few more questions pls. I've a white coating on the top of my tongue for over a month which doesn't hurt when I eat, drink or speak. In addition I've been getting a mild sore throat that comes and goes. I read online how a sore throat and white coating could be an HIV/STDs signs.

So at about 5 weeks and 4 days of my last protected exposure I took a full STD with HIV antibody tests which all came back negative except for herpes 1. I was wondering what the causes of these two symptoms?

My herpes to test was <0.90 and negative. Does <0.90 mean that I'm on the borderline that I may be positive in the future?

Thank you in advance for your help!
Answered by Dr. Michelle Gibson James 17 minutes later
Brief Answer:
NOT due to HIV based on tests

Detailed Answer:

White coating of the tongue is usually related to oral candidiasis ( oral yeast infection).
It occurs in any situation where the immune system is impaired in any way or if there is increased presence of this organism in the mouth. HIV is only one of the conditions is which this is found because of the immune impairment associated with HIV.

It can also occur in other cases: (1) diabetes (2) use of any immunosuppressant medication such as steroids , meds used in immune disease

(3)smokers and person with high carbohydrate intake- due to increased presence of the organism

(4)history of recent antibiotics



The test that you had done rules out HIV as the cause, so your doctor would determine if there are any likely causes such as those listed above.

Intermittent sore throat can be related to: (1) allergic sinusitis and post nasal drip
(2)viral infection like the common cold
(3)bacterial sore throat such as strep
(4)GERD- in severe case this can also cause reflux
(5)rarely oral candidiasis can spread to involve the throat, this can be identified by an ENT doctor

The herpes test result indicates that there is no current infection with herpes. It is not saying that you are borderline, it means that you are negative, not infected.

Please feel free to ask anything else
Above answer was peer-reviewed by
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