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HIV Test Result

Jun 25, 2007

I tested inderminate for my Western Blot. Though the test says Non-Viral Bands present, against all bands it says absent.And the specimen could not be determined positive or negative.

I am really worried, as I did not have sex in the past month and I do not think I had any chance of getting infected.

Also I did take a TB skin test that same day before the blood sample was taken. Will this affect my HIV test in any way.

Please advice as to what should I do as this is just driving me crazy.

Response from Dr. Frascino


Indeterminate Western Blot tests are not uncommon. I've addressed this issue many times in this forum. See below and check the archives for additional details if needed.

TB skin testing does not affect HIV test results.

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


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

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