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What does faintly positive HIV rapid test mean? Can pneumonia and bronchitis affect blood test results?

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What does a "faintly positive" result mean? What can cause a "faintly positive result"? The nurses and doctors were trying to tell me it's possible I just got it but I may or may not have it but then they started backpeddling again saying it's likely I do have it and could've just gotten it. The last time I had sex (condom came off....pretty sure it wasn't taken off) in early XXXXXXX of this yr. I can't remember if they told be where the line was faint but i was told the 1st test the line was slightly faint and the 2nd rapid oral test it was so faint they studied it for a really long time before they saw it like it was so faint they thought the 2nd test was conclusively negative. I've never had this happen before....any test i've ever been given before this recent doctor visit were negative. From XXXXXXX 2010 to XXXXXXX 2011 i've maybe had 4 to 5 'not-on-purpose' sex mishaps happen where condom broke or slipped off and was found or bed or came off inside of me & was pushed up. Some of those accidents were short (5 minutes at the longest) or pretty long (up to 45 mins). Probably stupid for me to wait up until a few days ago this yr to finally get tested again.

Also can a viral infection I had that recently gave me a case of acute pneumonia and acute bronchitis effect the rapid oral or pending blood test? Can you test accurately through urine also? And what are the most accurate and sensitive confirmatory blood tests can be done to be certain of an HIV result? I think i've asked everything I needed to. Thanks.
Posted Thu, 12 Apr 2012 in X-ray, Lab tests and Scans
 
 
Answered by Dr. Jasvinder Singh 50 minutes later
Hello,

Thanks for posting your query.

I can understand your concern for these rapid tests for HIV.

The testing for HIV is divided into primary or secondary tests. "ELISA is the primary test and if a positive test report comes on ELISA, then it has to be confirmed by a secondary test like western blot".

A false positive ELISA is possible if there is an autoimmune disease, multiple pregnancies, blood transfusions, liver diseases, parental substance abuse, hemodialysis, or vaccinations for Hepatitis B, rabies, or influenza. Any of these conditions can stimulate cross reacting antibodies.

Hence any viral infection can cause false positive rapid tests which are even less specific than ELISA. Western Blot test is quite confirmatory for HIV. Western Blot HIV tests usually look for antibodies against the following HIV proteins:

•     Proteins from the HIV envelope: gp41, and gp120/gp160.
•     Proteins from the core of the virus: p17, p24, p55
•     Enzymes that HIV uses in the process of infection: p31, p51, p66

In order for a person to be considered HIV positive, they generally need to have either antibodies against one of the envelope proteins and one of the core proteins, or against one of the enzymes.

Confirmation is only done by specific tests for HIV like ELISA, western blot, PCR and ELISA. These tests may show accuracy after 6 weeks to 6 months as HIV antibodies take time to develop in the body.

The bottom line is, in your case the positive result is to be confirmed with a second ELISA after a few weeks. If the second ELISA is positive, then Western Blot test must be done to ensure that the antibodies detected in the ELISA test are really HIV antibodies.

Hope this answers your query.

If you have additional questions or follow up queries then please do not hesitate in writing to us. I will be happy to answer your queries.

Regards
Above answer was peer-reviewed by
 
Follow-up: What does faintly positive HIV rapid test mean? Can pneumonia and bronchitis affect blood test results? 3 hours later
The biggest part wasn't particularly cleared/answered to me. "What does a "faintly positive" result mean? What can cause a "faintly positive result"? The nurses and doctors were trying to tell me it's possible I just got it but I may or may not have it but then they started backpeddling again saying it's likely I do have it and could've just gotten it". There is a difference in a faintly positive and false positive isn't it?

Can a faintly positive mean there is a chance I have it? Can they be able to tell if it's a false pos aftera 2nd ELISA, western blot, PCR and ELISA.

I guess i'm asking can they detect the actual virus past if someone has had the flu or a bad cold? I've been told a flu vaccine can't affect a result is that a yes?

Even with the flu or a cold a western blot is a better confirmatory than a pcr or elisa test?

I just would hope since it's been close to 6 months since i've last had sex an even with a bronchitis/flu and a flu vaccine that I am diagnosed properly.
 
 
Answered by Dr. Jasvinder Singh 5 hours later
Hello again,

Thanks for writing back to me.

A "faintly positive" test is not confirmatory and may be due to false positive tests because rapid tests are not very specific and may give false results.

Faintly positive result on a rapid HIV antibody test does not mean that you are HIV-positive without a confirmatory ELISA or Western Blot test, since 86% of these weakly positive results turned out to be negative when checked with a confirmatory test.

Hence every reactive (even faintly positive) rapid test must be confirmed by a supplemental test (either Western blot or immunofluorescence assay [IFA]). You should get a Western blot test done.

ELISA test can be affected by viral infections or viral vaccines but not western blot. Hence it is advisable to get it done.

Hope this answers your query.

If you have additional questions or follow up queries then please do not hesitate in writing to us. I will be happy to answer your queries.

Regards
Above answer was peer-reviewed by
 
Follow-up: What does faintly positive HIV rapid test mean? Can pneumonia and bronchitis affect blood test results? 1 hour later
I have a confirmatory blood test pending right now but I don't know what kind is being done I wish I did (ELISA or Western Blot not sure) which of the 2 is most effective as far as a confirmatory test?

I guess I will ask if the ELISA test for blood was done or the western blot. If they did the ELISA but not the western blot will a doctor do or send for a western blot if I ask?

86% of weak/faint positive oral results coming back negative with a confirmatory test is some relief.

Just to be clear a viral infection like flu/cold/bronchitis or vaccine can influence a oral result or an ELISA blood test but not a western blot or IFA?

How can it be possible for 2 back to back rapid oral tests to come back faintly positive? It's never happened to me before.

The other answers you've given me so far have been good enough....won't change whatever the results will be but has given me new insight to hiv testing. I have no more follow-ups so I guess this is it.
 
 
Answered by Dr. Jasvinder Singh 10 hours later
Hello,

Thanks for writing back.

Western blot is more confirmatory than ELISA and can be done.

If the doctors have sent the samples for ELISA, then you can always request for further testing by Western blot if the ELISA test comes positive.

False positive tests are seen when there are cross reacting antibodies to foreign antigens, proteins and infectious agents. Hence it can come as faintly positive.

Hope this answers your query.

If you have additional questions or follow up queries then please do not hesitate in writing to us. I will be happy to answer your queries. Please accept my answer in case you do not have further queries.

Regards,
Above answer was peer-reviewed by
 
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