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Positive elisa and Indeterminate Western blot
Mar 26, 2007

Hello I just found out I was pregnant and I took a routine Hiv test. I got the results for the Elisa test and they were positive and the Western blot was indeterminate. I am very shocked. The doctor said that only one protein strand came up showing the antibody. Im very confused. I had a tetnus shock about 8 months ago , could that be a reason that the elisa test came back positive. I havent been sexually active for 6 years execpt with my husband. Help?

Response from Dr. Frascino

Hello,

First off, please note a positive ELISA and indeterminate Western Blot do not constitute a positive HIV test! The test remains indeterminate. In your case, most likely you are HIV negative, due to the fact your risk is nearly nonexistent and the Western Blot pattern is most likely not consistent with evolving seroconversion. The most likely cause for your positive ELISA and indeterminate Western Blot is cross-reacting antibodies and/or pregnancy. The issue of indeterminate Western Blots comes up so frequently, it's almost reached QTND (Question That Never Dies) status. See below. Follow-up tests including a repeat serology plus, if necessary, a DNA PCR should be able to sort this out for you quite quickly. Try not to worry. Most likely you are HIV negative, OK?

Good luck.

Dr. Bob

Reprint:

1. Am I OK or What? (Indeterminate Western Blot) Feb 21, 2007

Am I ok or what?!? (INDETERMINATE WESTERN BLOT) Feb 21, 2007

Hi. I have always had negative hiv tests my whole life, including during a pregnancy in 1998 and another pregnancy in 2000. In 2003 I gave blood and it was rejected; a doctor visit showed inconclusive hiv/negative western blot. 4 months later a repeat showed the same results. In spring 2006, hiv test result was positive, western blot indeterminate. Doctor did a blood test called RPR which was nonreactive and HIV-1 RNA-PCR and HIV 2 test. All came back okay. Also saw an infectious disease specialist at that time. Both doctors agreed I do not have HIV in their opinions but cannot tell me why I went from negative to HIV inconclusive/western blot negative to HIV positive/western blot inconclusive over the course of my life. They say "you don't have hiv, don't worry" but can't explain it so I do worry about it. It seems like the blood tests are showing a progression over the years of some kind to me. I have constant swollen glands in my neck and lumps there also which another specialist determined through a scan were "not masses and nothing to worry about" but I also know that that is a sign of HIV. Because of my "weird" test results over the years I worry although I know swollen glands and lumps in the neck can also be results of sinus/allergies of which I do have other symptoms of (and I also have TMJ). I am tired of worrying and do not want to think of my HIV test results every time I get a cough or pain in my neck, etc.! I feel I am becoming a hypochondriac and I am stressed often about it. Do you have any advise as to my results over the years? Thanks so much.

Response from Dr. Frascino

Hello,

So the question is "Am I OK or what?!?" The answer is "OK," definitely OK. Your test results are not showing progression. Indeterminate tests are not positive tests by definition. The reason your multiple physicians have not given you a specific answer regarding your false-positive antibody test and indeterminate Western Blot is that there are many potential reasons, none of which is really important once we establish you are definitively and conclusively HIV negative. And that has been done. (See below)Whatever is causing your symptoms, one thing that's for sure: it's not HIV, OK?

Be well. Stay well. (Yes, you are indeed well!)

Dr. Bob

inderminate WB test (INDETERMINATE WESTERN BLOT) Feb 9, 2007

I tested positive in teh ELISA test and have an inderminate result in the WB test. In my opinion, I am a low risk person. In the past 3 years, I have had unprotected sex with 2 different guys, one being in the military, who has tested negative and one who was married for 10+ years before me. I am unsure what bands showed up on my WB test. What is the percentage of an inderminate WB test turning into a positive HIV test? I was told I could not get tested again for 3 months and I have asked my 2 recent sex partners to get tested.

Response from Dr. Frascino

Hello,

Indeterminate Western Blot tests account for 4% to 20% of Western Blot assays in various studies. The causes of indeterminate results include:

1. Serologic tests in the process of seroconversion; anti-p24 is usually the first antibody band to appear.

2. Late-stage HIV infection, usually with loss of core antibody.

3. Cross-reacting nonspecific antibodies, as seen with collagen-vascular disease, autoimmune diseases, lymphoma, liver disease, injection drug use, multiple sclerosis, parity or recent immunization.

4. Infection with O strain or HIV-2.

5. HIV vaccine recipients.

6. Technical or clerical error.

The most important factor in evaluating indeterminate Western Blot test results is risk assessment. Patients in low-risk categories with indeterminate tests are almost never infected with either HIV-1 or HIV-2; repeat testing often continues to show indeterminate results and the cause of this pattern is often not elucidated. For this reason, it's important to realize that HIV infection in situations like yours is extremely unlikely, although a follow-up test in three months is recommended to provide absolute assurance. Patients with indeterminate tests who are in the process of seroconversion usually have positive Western Blots within one month. DNA PCR may also be helpful for sorting out indeterminate serologic test results. An HIV specialist can help assess your HIV risk and interpret HIV test results if necessary.

Good luck.

Dr. Bob

indeterminate test result follow up (INDETERMINATE WESTERN BLOT) Feb 19, 2007

Dr. Bob,

I knew it!!! You were right..I called the lab and they told me that the walkin clinic had ordered the wrong test and did not run the screening HIV test. She told me sweetie you have nothing to worry about your HIV negative after looking at that and the viral load and P24. These clincs should not be doing this if they cant order the right dam test. Thanks for answering my post.

Response from Dr. Frascino

Hello,

You're welcome! I'm delighted another anxiety-provoking mystery has been solved. (Move over Sherlock Holmes, here comes Dr. Bob!)

Stay well.

Dr. Bob

indeterminate test results (INDETERMINATE WESTERN BLOT) Feb 17, 2007

I am a 24 yrs old heterosexual male. About 5 weeks ago I experienced a burring sensation in my urine after having non protective sex with a woman who now I am dating. I went to a walk in clinic and they prescribed me bacterium. After 1 week of that not working and a pain in my left side of my groin the clinic decided to do a whole STD test. Even a culture test for gonorrhea oh what fun!!(this was 14 days after the non protective sex)...6 days later I get my results back and I get a indeterminate test results(western blot) HIV on abnormal p24 and p40 nothing else. The doctor asks me my sexual history in the past 6 months and I tell them that the only person I was with was heterosexual sex with a college student that I am dating that had a STD check back in august and was negative for everything.(she says has only been with me since then) That day after telling me I don't have a lot to worry about he tells me we can do a antigen p24 test and viral load test just to make me feel a bit better. Both of these test with a standard blood test came back normal or negative. He reassured me again not to worry and to get another test in 4-6 weeks. I am an extremely high strung person and have been feeling a bit on the low side, along with a bit of sore throat and my tongue has been slightly sore. No fever or rash that I have seen on the Internet that goes along with a new infection. I don't know if these are factors of being extremely stressed about all this or a early HIV infection. What is your thoughts on the results of the negative p24 and viral load test based on my case. Also if I am negative what can throw the western blot of like this?

Response from Dr. Frascino

Hello,

You mention your indeterminate Western Blot result, but fail to mention if you had a positive ELISA test first! Western Blot tests should only be run to confirm a positive HIV-antibody screening test (ELISA or equivalent test). See below. This question unfortunately comes up far too often and reveals the fact that some clinics or physicians don't understand basic HIV testing and screening procedures!

Dr. Bob

I think I figured out the mystery Dec 12, 2006

Dear Dr. Bob... I appreciate so much, the information I have obtained from your forum...due to all of your generous responses to us worriers... I believe I may have solved the mystery of my indeterminate HIV tests. I wrote you a few days ago but have not heard back and I would love to hear your take on this situation for I am still a bit nervous. I am the female who has had two indeterminate western blot tests, the first being a weakly reactive p24 and the 2nd...two months later...being a weakly reactive p24 and p40. The day after I got my blood drawn for the 2nd test I was so anxious about waiting for the results that I went and got a unigold rapid test at a clinic, and the result was negative. So... I was baffled to hear I was indeterminate once again on the 2nd western blot and that this time, it seemed to have progressed a bit. I also had an ultra sensitive RNA test done a week after my 1st indeterminate western blot and that was negative. Yesterday, I went to see and infectious disease Dr. who is taking over my case from my OBGYN. She seemed to think I was negative but not really sure, and she drew blood for an HIV1/2 Elisa/Western blot. Well, today, I suddenly realized that my results from the two western blot results said nothing about an Elisa. Assuming the Elisa had been ran, I wanted to make sure and I called my OBGYN who had ordered the tests. She said she was pretty sure she only ordered a western blot...the lab then confirmed that I had not had elisas done.

I'm thinking...WHATTTT?? How can this happen...doesn't every Dr., especailly an OBGYN know that you have to run an elisa first? I've been distressed for 2 months!!! I'm hoping this means that I'm probably fine and that the rapid test result is more reliant?

I have to wait three weeks to get my Elisa result from the infectious disease Dr... and I'm hoping, in the meantime, you can shed some light on my situation. Do you think these reactions are HIV 1 or 2 and if not, should I be concerned about these reactions? All other STDs have been ruled out and the only person I could have gotten HIV from has tested negative on the orasure advance rapid 5 months out from his last partner and I haven't been sexual with him in almost three months. From reading your forum I learned that you must always run an Elisa first because Western Blots can yield a high amount of false positives if done without first getting a reaction from an Elisa?

Is this right? Does this mean I'm probably fine and I can breath again?

Thanks so much Dr. Bob for all you do... I will definitely make a donation when I am back to work and that's from the goodness of my heart and my true appreciation for you and your necessary services. And that is of course regardless of whether I receive a response from you. I read that someone actually accused you of only responding to those who say they're going to donate and that is a ridiculous accusation...it is appearant that you provide this service from the goodness of your heart to help those who need answers and suffering from anxiety.

Thanks Dr. Bob

Response from Dr. Frascino

Hi,

Congratulations on solving your own medical mystery using clues found in the archives!

The standard HIV-screening blood test consists of an EIA (enzyme immunoassay), like an ELISA, followed by a confirmatory Western Blot (WB). EIA screening requires a "repeatedly reactive" test, which is the criterion for Western Blot testing. Western Blot tests detect antibodies to HIV-1 proteins, including core proteins (p17, p24, p55), polymerase proteins (p31, p51, p66) and envelope glyco-proteins (gp41, gp120, gp160). Western Blot testing should always be coupled with EIA screening, because alone it has a 2% rate of false-positives. A positive WB is defined as reactivity at gp120/160 plus either gp41 or p24. An indeterminate Western Blot is defined as the presence of any band pattern that does not meet the criteria for a positive result.

Bottom line: you are HIV negative.

Be well. Stay well. Happy Holidays.

Dr. Bob

Indeterminate result Apr 25, 2004

Dear Dr. Bob, I recently had a HIV 1 test, and it came back as indeterminate. The results read "Viral bands observed, weakly reactive p31, HIV-1 Western Blot - indeterminate." I have been with the same person for the last 3 years, and we have both tested negative in the past. We do not engage in risky behavior (we don't do drugs, and we are monogamous). I don't feel sick and don't have any symptoms. However, I am very scared because of the result. What is the possibility that caused this result, and does the result mean that I may be HIV positive? What are my chances? Do I have any reason to worry? Thanks.

Response from Dr. Frascino

Hello,

Why did you have a Western Blot test done? Western Blots have a 2% false-positive rate. They must always be coupled with an ELISA test. "Indeterminate" Western Blot (WB) results can occur in 4% to 20% of assays. There are a variety of reasons why this occurs. Indeterminate results mean the test pattern does not meet the criteria for a positive result.

You have no identifiable risk factors for HIV. I do not believe you are HIV positive or in the process of seroconverting. (The anti-p24 is usually the first band to appear.) I do not believe you have any cause for worry. I would suggest you have an ELISA test. If negative, you can be reassured of your negative status. You should only repeat the WB if your ELISA is positive, which is highly unlikely.

Stay well.

Dr. Bob

inderminate WB test (INDETERMINATE WESTERN BLOT) Feb 9, 2007

I tested positive in teh ELISA test and have an inderminate result in the WB test. In my opinion, I am a low risk person. In the past 3 years, I have had unprotected sex with 2 different guys, one being in the military, who has tested negative and one who was married for 10+ years before me. I am unsure what bands showed up on my WB test. What is the percentage of an inderminate WB test turning into a positive HIV test? I was told I could not get tested again for 3 months and I have asked my 2 recent sex partners to get tested.

Response from Dr. Frascino

Hello,

Indeterminate Western Blot tests account for 4% to 20% of Western Blot assays in various studies. The causes of indeterminate results include:

1. Serologic tests in the process of seroconversion; anti-p24 is usually the first antibody band to appear.

2. Late-stage HIV infection, usually with loss of core antibody.

3. Cross-reacting nonspecific antibodies, as seen with collagen-vascular disease, autoimmune diseases, lymphoma, liver disease, injection drug use, multiple sclerosis, parity or recent immunization.

4. Infection with O strain or HIV-2.

5. HIV vaccine recipients.

6. Technical or clerical error.

The most important factor in evaluating indeterminate Western Blot test results is risk assessment. Patients in low-risk categories with indeterminate tests are almost never infected with either HIV-1 or HIV-2; repeat testing often continues to show indeterminate results and the cause of this pattern is often not elucidated. For this reason, it's important to realize that HIV infection in situations like yours is extremely unlikely, although a follow-up test in three months is recommended to provide absolute assurance. Patients with indeterminate tests who are in the process of seroconversion usually have positive Western Blots within one month. DNA PCR may also be helpful for sorting out indeterminate serologic test results. An HIV specialist can help assess your HIV risk and interpret HIV test results if necessary.

Good luck.

Dr. Bob

2. INDETERMINATE WESTERN BLOT Mar 5, 2007

INDETERMINATE WESTERN BLOT. Mar 5, 2007

HI I have been diagnosed as HIV positive by 2 doctors and as HIV Indeterminate by one doctor, in the same town, in the last few weeks, based on blood test results that came back with the same findings to each doctor. I do not know if I am HIV positive or HIV Indeterminate. I am HIV positive on Elisa and my western blot is positive for P24 and GP 160 (not gp120). All 3 doctors found these results independantly and just interpreted the results differently. I tested HIV negative on Elisa on October 21st 2006. I tested HIV positive on Elisa January 15th 2007 and this was followed shortly after with the western blot results above. Going back carefully over my sexual history the only time since June 2006 up to today, that I could have been infected was one sexual encounter around October 20th 2006 with a male (well transexual) prostitute. We used a condom, both of us. We performed oral sex on each other withouth a condom and withouth ejeculating. I am hetrosexual and my current partner tested HIV negative this week . We have been using a condom since my positive elisa test on Jan 15th and had unprotected sex last time on Jan 7th. The doctor who declared me HIV positive declared her with a 98% chance of being HIV free because its about 7 weeks since the last possible time of infection. Is he correct? What about me? Am I indeterminate or posiitive? I would like to ad that I was not immunized as a child and from September 2006 started to get immunization for just about everything. taking 4 or 5 shots at a time (Rabies, hepatitise A,B, etc.

Thanks

Response from Dr. Frascino

Hello,

I can't tell from your post if you've had three separate tests or just three separate opinions on the same test results.

Here's what I can say based on the information you've provided:

1. Your HIV risk would be negligible, if indeed your only potential HIV exposure was a single episode of condom-protected tranny-sex and unprotected bilateral oral.

2. The interpretation of confirmatory Western Blot tests is as follows:

a. Negative equals no bands.

b. Positive equals band reactivity to gp 120/160 plus either gp41 or p24.

c. Indeterminate equals any band pattern not meeting the criteria for a positive test.

3. The sensitivity of HIV Western Blot tests is 99.5% and the specificity is 99.994%.

4. False-positive results for both ELISA plus Western Blot range from 0.0004% to 0.0007%.

5. The causes of false-positive tests can include autoantibodies, HIV vaccines, factitious HIV, technical error and clerical error.

Could your recent vaccinations cause false-positive results? It's more likely that vaccine-induced antibody production may cross react on an ELISA test than on an HIV-specific Western Blot.

At this point, if the situation remains uncertain or disputed, I would repeat the ELISA and, if positive, the Western Blot plus get an HIV plasma viral load and T-cell subsets analysis. If that doesn't definitively resolve the issue, I'd suggest you have your entire medical record reviewed by an HIV specialist.

Keep us informed of your evaluation, OK?

Good luck.

Dr. Bob



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