Rapid test vs EIA test

[asmith12]

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.

[regularjoey]

Indeterminate results usually mean positive EIA and partially positive WB.  Indeterminate results always have to be followed up at a later timepoint.  I suggest taking a standard EIA/WB at 3 months post-exposure.  If the WB stays indeterminate, that would indicate that you don't have HIV.  Best of luck!

[Teak]

Of course ELISA test can be indeterminate. No an ELISA test is not that much different than a Rapid test. One takes a machine to process while the other doesn't.