inconclusive western blot (INDETERMINATE WESTERN BLOT)
Jun 20, 2007
Elisa was positive, so western blot was done and came back inconclusive, then the same results in a month and then in 3. What does this mean
Response from Dr. Frascino
This is not an uncommon problem. See below.
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
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!
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
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.
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
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.
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
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.
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