Here a monitor shows the results of blood tests for various diseases, including Zika. Both blood and urine can be tested for presence of the Zika virus. (AP Photo/Arnulfo Franco, File)
Imagine being pregnant, getting tested for Zika, feeling relieved when you find out that the test is negative, but then months later hearing that your test was actually positive. Well, as the Washington, DC NBC affiliate reports, that’s now happened to at least two women. After Dr. Anthony Tran became Director of the Washington DC Public Health Laboratory in the latter half of 2016, he found an error in the laboratory’s Zika testing procedure. This meant that 409 specimens from July 14 to December 14, 2016, that had previously been deemed negative for Zika have had to be re-tested by the Centers for Disease Control and Prevention (CDC) or CDC-approved labs. So far, according to the Washington Post of 62 re-tests, 2 have come back as positive.
Since January 2016, many doctors offices, hospitals, clinics, and other healthcare organizations in the Washington, DC, area have been sending specimens to the Public Health Laboratory for testing. Of the 409 specimens, 294 were from pregnant women. As Dr. Tran told the Washington Post, “the error was a technical formulation and calculation error that I discovered after I got here.” Dr. Tran was previously Director of Policy and Operations at the New York City Department of Health and Mental Hygiene before moving to DC in September 2016. The test is complex so re-testing will take several weeks, meanwhile leaving many people on pins and needles (not literally but figuratively).
Here’s the problem. You get tested for Zika to make time-sensitive decisions. You may want to know what precautions to take given that Zika can potentially be transmitted by sex or blood transfusion. If you are pregnant, you may want to determine what to do with your pregnancy since the Zika virus may cause birth defects. A false negative test would give you false confidence that you are in the clear and may not need to take precautions. What happens when you discover weeks or even months later that the test was actually positive and can no longer undo your previous decisions? Yes, a mistake on a test could dramatically alter the course of your and others lives. Currently, there’s no evidence that laboratories elsewhere have had the same error, but they all may want to double-check their procedures.
There are several take home messages here. First, no test is perfect. Every test, even when performed perfectly can return a negative result when it should be positive and vice-versa. Add to that the possibility of human and machine error. Therefore, don’t base everything on one test. That’s why it is helpful to have a doctor help interpret your test results. The doctor can evaluate you and recommend other testing depending on your history, other risks, and concerns. for example, tn the case of Zika, a doctor can order an amniocentesis or ultrasound in the course of your pregnancy. A second is that the lack of Zika funding has had its impact. If you recall, political squabbling in the Senate and Congress caused over a half year of delays in Zika funding. While its unclear whether swifter and more funding may have prevented these specific laboratory errors, you have to wonder what kind of cascade effect may have occurred. Many overburdened public health laboratories are short on staff and resources, making it more difficult to prevent and catch errors. Last year, while waiting as the legislative arguing went on and on, the U.S. public health infrastructure had to struggle to combat the rapidly spreading Zika epidemic (while still dealing with many other diseases and problems) without much support. Third, the Zika epidemic caught everyone by surprise. We’re still learning about the virus, its transmission, its health effects, and its testing. Without enough funding available, many scientists couldn’t do the necessary research fast enough.
The shortage of resources for studying, preventing ,and controlling Zika has not changed. Yes, Zika is no longer making the headlines as it did last Summer. But like an incorrectly negative Zika test result, don’t let this decreased attention give you false confidence. Zika isn’t going away anytime soon. In fact, it continues to silently spread, and you may be surprised about what you find in the future.
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