DETROIT – Three million rapid COVID-19 tests are on their way to Michigan.
The tests were sent as part of the White House plan to increase testing capacity in certain settings.
The rapid tests are produced by Abbott Labs and are called the BinaxNOW COVID-19 Ag Card. There was a prior Abbott rapid test called the ID Now, which had been criticised in some studies for an unacceptable rate of false negatives. These newer tests being distributed now are different.
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The BinaxNOW test is a single, test, about the size of a credit card, that doesn’t require any special equipment to interpret. A nasal swab is used and the test detects a specific protein that’s on the surface of the SARS-CoV-2 virus in 15 minutes.
The ID Now system, also from Abbott, is a rapid PCR test. It detects something different, the RNA, or genetic material of the virus. No test is 100 percent accurate.
The standard PCR tests that are done in a lab are more accurate and considered the gold standard. They have a low false negative rate, meaning they correctly find infected individuals. The problem is they take longer and require special equipment and reagents.
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The new rapid tests don’t require any special equipment and only take about 15 minutes. Unfortunately, what they gain in speed and convenience, they lose in accuracy. Abbott said their BinaxNOW test has a low false negative rate of only 2.9 percent within 7 days of symptom onset. There haven’t been any independent tests to verify that.
The clear advantage is that a widely available rapid test can be used in settings like schools, critical infrastructure workers and long term care facilities to screen for infectious people whose infection is in early stages or who might otherwise be undetected.
No one should ever rely on one of those tests to prove that they aren’t infected. They aren’t sensitive enough for that. If someone screens negative they still need to wear a mask and maintain social distancing practices.
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