EDITORIAL – ‘False negative’: The danger of inaccurate HIV tests

There are few things more frightening than knowing you have HIV … unless it’s having HIV and not knowing it.

As reported in Tuesday’s Compass, the news that the Health Services Authority discovered three cases of “false negative” HIV tests from private healthcare facilities in the Cayman Islands is cause for great concern.

Cayman’s top public health officials – Acting Medical Officer of Health Dr. Samuel Williams-Rodriguez and Acting Chief Medical Officer Dr. Elizabeth McLaughlin – were correct to publicize the existence of the “false negatives” and to provide information on how to obtain accurate HIV tests.

Too often, government’s instinct is to downplay (if not outright cover up) incidents that might reflect negatively on the country. On the other hand, in the past we have expressed concern about government’s “overplaying” of certain health news, such as fears over Ebola and Zika. However, in regard to the erroneous HIV tests, officials made the right call.

“These ‘false negative’ persons pose a public health risk to the Cayman Islands,” they said. “As such, there is a need for the standardization of kits used in HIV-testing in healthcare facilities.”

In case the situation is not clear, what happened is that three people in Cayman went to private health clinics and underwent testing for HIV (the virus that causes AIDS). The results were “negative” – meaning they were cleared of carrying the disease.

Unfortunately, the results were wrong. As part of a standard verification process, the samples for the three people were re-tested by HSA, with the results being HIV “positive,” and confirmed by HSA’s reference laboratory in the United States.

Although HIV is a serious condition, the good news is these three people are now armed with the knowledge necessary to seek effective medical treatment for themselves, and to prevent further transmission of the virus.

Inaccurate HIV tests have surfaced as a significant problem outside of Cayman. In late January, the Mexican government seized nearly 47,000 Chinese-made HIV testing kits that officials said “could give false negatives and put at risk the lives of patients who didn’t receive medical treatment,” according to the Associated Press.

(That being said, we don’t have enough information to determine whether the false negatives in Cayman resulted from “bad testing kits,” clinician error, or other causes.)

While three false negatives in Cayman may not seem like a large number, it is significant in the context of the prevalence of HIV in this country. For example, over the past decade, about six new cases of HIV are diagnosed on average each year in Cayman.

As of 2015, there were 66 people living with HIV in Cayman, plus 19 HIV patients off-island whom the HSA is tracking. The incidence rate of HIV in Cayman is relatively low, compared to large nations such as the United States and United Kingdom.

A primary reason for that may be because HIV tests are a mandatory requirement for work permit applications and other immigration documents, meaning about half of Cayman’s population (i.e. the expatriate half) is being tested on a regular basis. The more than 900 permanent residence applicants are tested every six months as they await decisions from government on their applications.

Of course, no matter how often people are getting tested, that lends little security if the results of the tests aren’t accurate. All of our healthcare providers, both public and private, should be providing tests (for HIV or any condition) that can be trusted.

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2 COMMENTS

  1. There are two things that the government allow to happen that I do not agree with in the processing of work permits.
    One: The government should make it mandatory that all work permit, permanent residence applications and status applications, medical works are carried out at the CIHS not at private hospitals.
    Two: The government should send email with batches of names of persons to their respected countries for police clearance, and the cost be added to the work permit application. People are getting work and many of them does not have a clean police record where they come from.

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  2. Unfortunately false positive and false negative results are an issue with every medical test.

    Especially where the incidence of the condition is rare.
    For example the PSA test for prostate cancer has a very high false positive error factor.
    3 out of 4 men who have an elevated PSA level do not have prostate cancer

    https://www.theprostatecentre.com/prostate-information/the-psa-test/problems-with-the-psa/

    But there are other men who do have prostate cancer but their PSA is lower. A false negative.

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