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A rapid test for the novel coronavirus that was unveiled by President Trump on the White House lawn and has already been used hundreds of thousands of times can falsely produce negative results in patients who are infected, according to clinicians and laboratory experts.

The 13-minute test, developed by Abbott Laboratories, a major U.S. health care and medical device company, usually still works properly, the company and clinicians say. But Abbott’s initial guidance on how to administer the test — guidance approved by the Food and Drug Administration — could lead to an unspecified number of false negative results. Abbott says changing how samples are collected should fix the problem.

The test “performed equivalent to the other platforms with patients that had high and moderate loads of virus,” said Alan Wells, a pathologist who directs the clinical laboratories at the University of Pittsburgh Medical Center. “However, with lower loads of virus, a large fraction of these patients were not detected as positive.” Wells ran a validation of the test compared with stored samples that had been tested on other platforms.


In recent weeks, clinicians have expressed growing concerns about false negative results in testing for the coronavirus, known as SARS-CoV-2. Much of the problem has been blamed on issues with how samples for the main laboratory tests are collected. 

Since Abbott’s test, run on its “ID Now” platform, was granted emergency use authorization by the FDA on March 27, the company has shipped 600,000 tests. They are being used at CVS and Walgreens drive-through testing locations, to test nurses and police officers in Detroit, and at urgent care centers in Chicago. They are also being used in hospitals to test surgical candidates to determine if they should be operated on and what level of protective equipment physicians should wear.


The test can be used in two different ways. In one method, a swab that has been rubbed against the nose, throat, or the area deep in the back of the nose is inserted directly into the ID Now platform, a toaster-sized machine. That approach is still seen as effective. 

But the FDA cleared the test to be used in another way: The swabs could be put in a liquid solution — known as “viral transport media” — and tested, which is the standard way for processing many other kinds of tests and usually allows samples to be stored longer.

In a letter sent to health care providers Wednesday, obtained by STAT, Abbott said that the test should not be used in the solution because it could lead the test to give a negative result when a patient is actually infected. The company said it will work with the FDA to change the language of the product’s package, and intends for changes to be made by the week of April 20.

The letter says the issue was discovered as the new customers conducted validation tests.

In a statement, Abbott said that when that when the collection method is not used, “the test is performing as expected and we have confidence in the performance of the test.” It also stated that the ID Now platform is designed for and typically used in “urgent care clinics, physicians’ office labs, emergency departments, and retail settings,” where collection with transport media would not occur.

There is little doubt that when the ID Now coronavirus delivers a positive result, that means a patient is infected with the coronavirus. The question is how secure patients and doctors should feel with a negative result.

Wells, the pathologist, said that the University of Pittsburgh Medical Center is now not using the ID Now to rule out whether patients are carrying SARS-CoV-2, but will consider using the machine to identify patients to enroll in clinical trials. For testing surgery patients, it is using another testing machine, from Cepheid, that can return results in 45 minutes.

On an April 8 webinar by the Society for Maternal Fetal Medicine, one of the participants, Emily Miller, an OB-GYN at Northwestern, said her institution had a similar experience with the Abbott ID Now test, saying that its sensitivity (the ability to not miss infections) was “clinically not useful” for determining if pregnant women were infected.

“So we have not moved forward with it,” Miller said. “But I think the lesson there is it’s incredibly important to validate whatever test it is with your existing population and make sure you’re troubleshooting before you’re actually using that information clinically because I shudder to think — the path we would have gone down.”

Neither Miller nor Northwestern’s medical school responded to an email requesting comment.

Michael Misialek, a pathologist at Newton-Wellesley Hospital in Massachusetts, which is part of the Partners Healthcare system, said that he had run his own validation of the ID Now Covid-19 test and that the machine’s results compared favorably to other diagnostic devices. However, Misialek said, there was one sample where there was not agreement. He decided that the result could be related to over-dilution — the issue Abbott later warned about. His hospital took to sending the swabs dry, not in viral transport media.

“I think the important point is all these assays have been emergency release by the FDA,” Misialek said. “So they haven’t gone through the traditional rigor of studies, and validations and certainly not extensive comparisons. But right here, at Newton-Wellesley and my colleagues across Partners, we haven’t seen anything to date that worries us.”

He currently uses both the Abbott ID Now device and the Cepheid one when his hospital has a patient with Covid-19 symptoms and a decision needs to be made about whether they need to be admitted, or to which part of the hospital. Supplies of test kits for both devices are limited, he said. 

That means that health care professionals collecting samples must know, one day at a time, whether they need to collect dry swabs, for the Abbott device, or swabs in transport media, for the Cepheid one. Abbott has said that by June, it will be able to produce 2 million tests a month, about a fifth of the total number of Covid-19 tests currently being run in the U.S.

“It really goes week by week, and we will look at our supply, estimate what the usage has been and be in touch with the inpatient teams, letting them know where we are and what we’re going to use or not,” he said.

Does anyone know how many patients the diagnostic tests miss?

“I’ll tell you, my pathologist colleagues are asking the same question,” Misialek said. “And I don’t think anybody has a good sense of what the clinical sensitivity of not only the Abbott [test], but all these tests are.

Gideon Gil contributed reporting.

  • What level of evaluation and validation must the manufacturer provide to FDA ? The evaluation data needs to be available on line for users to review. Users should not need to do a full validation before using the test.

  • The Title of this article is misguiding and should be: “Health Care Workers Botch ID NOW Tests” What must be clear is the fault is in the collection of samples and sample application for testing, NOT the ID NOW itself. Health Care Workers should never use Viral Transport Media. Also, ABBOTT has testthat determines antibodies for COVID-19 immunity which I’d like to know if this is done by the same ID NOW tester? If so, I that’s very useful so ppl can get back to work and give plasma for those in hospital.

  • Sensitivity and specificity should be published for any test.

    With all the broo haa haa in the news about testing, this is the first article I’ve seen that even uses one of these words.

    • I agree. In addition, the test should specify how the specimen should be collected and with what kind of swab. Collection using a dry swab will provide very different results than those using viral transport media (which dilutes the specimen). The manufacturer must have validated use of viral transport media before the user can use this or else the end user has to validate it’s use. This is why just anyone shouldn’t be collecting a nasopharyngeal specimen. It isn’t a throat swab and if throat swabs are collected you’ll get a lot of false negatives.

  • What is the sensitivity and specificity of the test? No test will be 100% sensitive meaning there will be a certain percentage of false negatives and false positive results. As the prevalence of the disease in the testing population varies, there is a trade-off between the # of false positive and false negative results. Increasing test sensitivity increases the number of true positive (TP) test results and this is even greater in a setting where the disease prevalence is high vs a setting where the disease prevalence is lower.
    As test specificity decreases, the number of false positives (FP) increases when disease prevalence is low, but a lower # of FP when disease prevalence is higher.

  • Trump with fanfare unveiling a product that has been used hundreds of thousands of times already truly fits this odd President’s mould: far behind the 8-ball – again / still. Almost guaranteed he owns the testmaker’s stock that went up $5US (5.5%) today (and 50% since March 28). The false negatives potential shows it is not the perfect test either. Joke of the day !

  • Experts have stated that the nose swab needs material from very deep / high up in the nose. I do not see swabbing beyond inside of nostrils in the drive-through action shown often on TV. So I would assume that samples not taken from the right spots also result in false negatives, defeating the purpose of testing.

    • I agree; the “nose” swab should be a nasopharyngeal swab and requires proper training to be done correctly. It is not a throat swab which, needless to say is probably done by drive through lab techs or technicians who haven’t been trained properly, thereby leading to false neg. results. Lab techs are not supposed to collect specimens. They can direct someone in the proper collection of a specimen or indicate whether someone should be fasting before a blood specimen is collected, but the actual collection should be left to the clinician. A nasopharyngeal swabbing is done with a small tipped swab and is not a pleasant experience. I would bet that either nasal swabs are being collected, which are not deep enough and do not consist of the appropriate cells or throat swabs are collected which are also inappropriate – both adding to the increased number of false neg. results. Nasopharyngeal swabbings should be done by a physician or nurse practitioner trained in the proper collection.

  • The truth is, they are not testing everyone with symptoms. I have symptoms consistent with COVID19 and when I asked about testing, they said NO. They are telling people with symptoms to “ride it out at home”. Those numbers of cases of COVID19 that get reported in no way captures even a majority of actual cases.

    Instead of focusing on re-opening, maximum effort needs to go on PPE, Ventilators, and tests. We sufficient tests, societies will re-open on their own.

    • Note what it says in the article- it’s all about where to put a patient that is being hospitalized. Tests are needed to know if medical staff need protective gear and quarantine procedures to treat a seriously ill patient. Mild symptoms not needing hospitalization are not on the radar. The bonus is that they aren’t able to calculate the full extend of the mild or asymptomatic coronavirus cases. The numbers are a lot scarier when they can underestimate the cases and overestimate the deaths to include ‘probable’ cases.

  • While the CDC test looks for the so-called coronavirus N gene and the WHO test goes after the coronavirus E gene, both can be hunted down by CRISPR.
    Much like how it is typically used to edit genomes, CRISPR then gets to work cutting the coronavirus genes to try to prompt a reaction that displays whether COVID-19 is present.
    It makes the CRISPR test more likely to miss people with lower levels of the virus – most likely those right at the beginning or the end of their infection.

    Use a mask if you didn’t get one yet here is where I got it:

    Until we get a vaccine, which is a while off, this is going to be our new normal, and we need to adapt and protect ourselves.

  • Abbott says changing how samples are collected should fix the problem.
    Lie. It was rushed and White House still promoting “perfect” machine. Junk Science just like Theranos Edison box. Walgreens still hasn’t learned their lesson.
    Direct swabs still a problem, this will come out shortly. Stay tuned.

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