The Body: The Complete HIV/AIDS Resource
Follow Us Follow Us on Facebook Follow Us on Twitter Download Our App 
Professionals >> Visit The Body PROThe Body en Espanol
Ask the Experts About

Understanding Your LabsUnderstanding Your Labs
Rollover images to visit our other forums!
Recent AnswersAsk a Question
  • Email Email
  • Glossary Glossary

Reactive Elisa, Non-reactive Western Blot

Apr 20, 2001


I have posted so many questions on this web site and no one has ever responded. Please help me.

I went in for an HIV antibody test 90 days after possible exposure. The result came back reactive on the Elisa but non-reactive on the Western Blot. They asked me to take another test 6 weeks later to confirm my status.

Here are my questions in the light of this.

1. Is the HIV antibody produced by the human body unique or is it one that is generic and produced in response to a number of other viral/bacterial infections(I had a rash on my face, and some inflammation on my penis when I went in for the test)? If the latter is true what are those viruses/bacteria or infections? What about antibodies to cancer?

2. What is the difference between the Elisa and the Western Blot tests that they both produce different results?

3. Is a reactive Elisa and a non-reactive western blot a cause for concern? What are the chances of the western blot getting reactive 6 weeks later?

4. Does an overall positive test mean that the Elisa gets reactive first and then the western blot after a few weeks or can both tests get reactive using one sample at one time?

I had a very low risk exposure. No sex, no needles. But some contact with an object that had some infected vaginal secretion that was dry but not too long after it was deposited. My skin was broken. I feel weak and look very thin and I've been stressed to the max.

Hoping to hear from you. Thanks a lot.

Response from Dr. Holodniy

1. Antibodies to HIV are unique to HIV. However, there are certain conditions (cancers, autoimmune diseases, or other viral infections like HIV-2, HTLV-1, HTLV-2), which could produce antibodies which react in a HIV-1 assay and cause a false positive. 2. ELISA is a screening antibody test. It gives a qualitative result that shows there is reactivity. It must always be followed by a confirmatory test such as a western blot which defines the specific antibodies to HIV-1 that are present, if any. 3. Only very minimal concern. That is why a followup test is recommended. 4. Both are usually positive at around the same time. Although the positive ELISA is what triggers the western blot to be performed. Sometimes during acute infection the ELISA can be positive, but the western blot indeterminate, meaning there are some antibodies present, but not enough different kinds to call it positive.


  • Email Email
  • Glossary Glossary

 Get Email Notifications When This Forum Updates or Subscribe With RSS



This forum is designed for educational purposes only, and experts are not rendering medical, mental health, legal or other professional advice or services. If you have or suspect you may have a medical, mental health, legal or other problem that requires advice, consult your own caregiver, attorney or other qualified professional.

Experts appearing on this page are independent and are solely responsible for editing and fact-checking their material. Neither nor any advertiser is the publisher or speaker of posted visitors' questions or the experts' material.

Review our complete terms of use and copyright notice.

Powered by ExpertViewpoint