False Negative HIV Results

sleepyRN2 · Aug 15, 2009

i think what the doctor meant is that she has been "positive" for hiv for many years (5yrs?). However, due to the patient's low viral load and high T cell count as to make them undetectable by the best hiv test in existence that the previous test results have "proved" negative by virtue of the test's ability in detecting viral load and T cell count, i'm assuming more of the former. easily put, the doctor is right that she's been positive for so many years but remained undetected until the viral load increased and t-cell count decreased as stated by the first positive test result. it's a definite weird case scenario but plausible nonetheless.

BabyLady, BSN, RN · Aug 15, 2009

A female patient tested positive for HIV. The Doc states that due to the patient's T cell count and Viral load, she must have been positive for many years. However, the pt is tested annually for HIV and all tests have been negative. Last negative test about 6 months ago. All laboratory results are in the patient's chart. So, is it possible that her last 5 negative test results were false? Is the Doc wrong in his estimate? Is this common? If so, how can we advice patients with faulty test results? Sorry about the list of question.

I actually don't believe that the physician can make such a claim, in fact, everything we know about the disease process of AIDS and HIV testing, says he is very incorrect.

People respond differently when they contract HIV....we now have people who have been HIV positive for over 20 years who are completely asymptomatic, and others who are dead less than a year without treatment or dead in a just a few, even with treatment.

I think he is misleading that patient into thinking that she doesn't need to look very closely at her most recent sexual partners.

If what he is saying is correct, then testing blood for HIV is worthless.

As of now, the most sophisiticated HIV testing can test a patient accurately within 90 days of exposure.

I just flat out don't believe that a woman can test negative 'FOR YEARS' and still have the virus.

Meriwhen, ASN, BSN, MSN, RN · Aug 15, 2009

My guess is that she probably WAS indeed negative all those years, but when she finally contracted the virus it hit her hard.

One false negative is something that could happen to anyone...and the risk of that happening is very low--usually it occurs because the person tested too soon (i.e., less than 6 months after exposure to the virus).

Many false negatives in the same person over many years just does not sound plausible at all. Maybe she's a medical anomaly and it's possible...but I highly doubt it.

heron, ASN, RN · Aug 15, 2009

I actually don't believe that the physician can make such a claim, in fact, everything we know about the disease process of AIDS and HIV testing, says he is very incorrect.
People respond differently when they contract HIV....we now have people who have been HIV positive for over 20 years who are completely asymptomatic, and others who are dead less than a year without treatment or dead in a just a few, even with treatment.
I think he is misleading that patient into thinking that she doesn't need to look very closely at her most recent sexual partners.
If what he is saying is correct, then testing blood for HIV is worthless.
As of now, the most sophisiticated HIV testing can test a patient accurately within 90 days of exposure.
I just flat out don't believe that a woman can test negative 'FOR YEARS' and still have the virus.

I want to expand on this great post a little bit. In the interests of full disclosure, I worked with people with HIV for about 13 years or so between 1986 and 1998 ... just a little bit after the beginning of the epidemic. I mention that because my info may be outdated and should probably get checked.

If they are still using the old ELISA test for HIV, or a variation on it, then the test detects antibodies to the virus itself. Viral load and cell counts have nothing to do with it and can't be "guesstimated" based on the screening test.

Manifestation of high viral load and abnormal t-cell counts is a late manifestation of the infection. As babylady pointed out, there are men with HIV who have had positive screening tests and yet have not progressed to clinical disease at all.

Effective antiretroviral therapy has been around so long that we think of AIDS as a long-term, chronic disease.

Untreated, the infection can progress like wildfire ... in the mid-80's before AZT hit the market, the average length of survival from seroconversion (the time between when antibodies are first detectable) and when the person died was something like two years.

And don't forget ... the virus has had 10 years (about when AZT came out) to evolve new tricks. For all we know, the virus currently in circulation isn't necessarily going to act like the virus that was around 10 to 20 years ago.

The course of the infection is also heavily influenced by the underlying state of health or disease of the woman herself. If she's getting routinely tested over a period of years, she's likely to be in a defined high risk group. Among women, that includes substance abuse, a sexual relationship with a high risk partner, or is a sex-worker.

Pregnancy also seems to accelerate the progress of the disease ... in fact, many women didn't think they could be infected because they had only one partner and assumed that he was both uninfected and faithful. They never knew that both they and their babies were infected until problems came up for one or the other.

I like to think that HIV testing is pretty routine pre-natal care, but it gets tricky and there's no legal mandate for it that I know of, so I suspect a lot of women fall through the cracks. CDC might have some info on that.

OP, what a great question ... is this the kind of info you were looking for?

bconcerned · Aug 15, 2009

Thanks for all your responses. I guess my main question is: Is it possible to be HIV positive and test negatively for years out side of the seroconversion window of about 6 months. Or is it possible for her T cell count to be low and viral load high because she is already ill. Even if she's only been infected for 6-8 months.

The patient was tested annually as a part of her annual physical not due to her risk status. The Dr includes HIV and STD testing in the annuals.

talaxandra · Aug 15, 2009

6 months is th outermost window - 99% of people seroconvert within 3 months of exposure, the majority of those in a month or so. Current false negative rates affect approximately 0.003% of those tested - the odds of her testing negative on multiple occasions is statistically borderline impossible.

heron, ASN, RN · Aug 15, 2009

Thanks for all your responses. I guess my main question is: Is it possible to be HIV positive and test negatively for years out side of the seroconversion window of about 6 months. Or is it possible for her T cell count to be low and viral load high because she is already ill. Even if she's only been infected for 6-8 months.
The patient was tested annually as a part of her annual physical not due to her risk status. The Dr includes HIV and STD testing in the annuals.

Yes, the infection could have progressed that fast.

And, good for that doc!

BabyLady, BSN, RN · Aug 15, 2009

My guess is that she probably WAS indeed negative all those years, but when she finally contracted the virus it hit her hard.
One false negative is something that could happen to anyone...and the risk of that happening is very low--usually it occurs because the person tested too soon (i.e., less than 6 months after exposure to the virus).
Many false negatives in the same person over many years just does not sound plausible at all. Maybe she's a medical anomaly and it's possible...but I highly doubt it.

This is EXACTLY what I think happened.

I agree with you 100%