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Rapid test vs EIA test

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Against my better judgement, I had unprotected sex in late April of this year. six and a half weeks later, I went to my county's health dept. and asked for an HIV test (in addition to other STDs). They took blood from my arm and sent it to a state run lab and told me to check back in two to three weeks.

About three and a half weeks after that, I checked with them and they informed me that the results were "pending" and that the state lab sent my blood to the CDC for further testing. They gave no further explanation. Feeling nervous, I went to another clinic and took a rapid HIV test. They pricked my finger and took a sample of my blood. Twenty minutes later, the counselor said that the results were negative for HIV. I asked her was she sure and she indicated a high level of certainty. This test was done exactly 10 weeks after the potential exposure. Two days later, I get a call from the county health department and they informed my that the state lab tested my blood twice using the EIA/ELISA method and both were indeterminate. They then twice performed the Western Blot test and both of those were indeterminate... which is why they claim it was then transferred to the CDC for further testing. They indicated that the results from the CDC would be back in four to six more weeks!

Being that the rapid test was taken closer to the 3 month mark, and was negative, why were four tests by the state lab (taken much earlier) indeterminate? Is the rapid test that much different from the EIA/ELISA test? Also, based on my limited research over the past month, I've never come across anything that would indicate that the EIA/ELISA test could be indeterminate. It is usually positive or negative. I also find it strange that the state lab has involved the CDC.

Any thoughts on this would be greatly appreciated.
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replied July 14th, 2008
Extremely eHealthy
If a person has an indeterminate HIV test result, the test should be repeated.
You can ask about a PCR (Polymerase Chain Reaction) test, also known as a "viral load, to be performed, cause this test looks for HIV directly in a person's blood instead of detecting antibodies (the body's reaction to HIV), and it may detect an HIV infection about a week after an exposure.

There are different reasons for indeterminate test results.

Have you been going through a viral infection soon before taking the blood sample for testing?
Are you a diabetic or having other medical problem?
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replied July 14th, 2008
I had been battling an upper respiratory infection about a week before I gave the blood sample. I had a full medical exam/physical in February 2007 and I was not diagnosed as being diabetic.... blood sugar was 89 or 90.
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replied July 15th, 2008
Extremely eHealthy
An indeterminate result means that the antibody test was neither positive nor negative.

This may be a result of:
problems with the test procedure itself, such as contamination of the blood sample;
prior blood transfusions, even with non-HIV infected blood;
prior or current infection with syphilis, malaria, or other viruses.

It'll be the best to repeat the HIV testing.

Best wishes!
Marija
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replied February 5th, 2012
It takes 3 months to develop antibodies against HIV in 97% of people. The other 3% can take up to 6 months to develop these antibodies. Both ELISA/EIA and Rapid HIV test detect antibodies against HIV. If either of these tests are performed within the window period, chances are that they could be indeterminate or falsely negative. It is recommended to get an HIV test after 3 months. Since you took the Rapid test around 3 months, it gave you a result which could be true or false. I recommend getting a follow up test. The ELISA was done way too early for it to have picked up anything.
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