By Jacob Nakamura
(Tumon, Guam) The manufacturer of the machine GovGuam has been using to run COVID-19 tests from both Guam and Saipan just issued an emergency notice that its machines may shoot out false negatives the way the tests are run on Guam.
According to public health director Linda DeNorcey, two Abbott ID NOW machines currently are in operation by the government for public use; one at a public health laboratory in Tamuning, and another at Guam Memorial Hospital. A third machine is in use by the Guam National Guard.
COVID-19 test specimen are taken from clinics and sent to the public health lab in Tamuning to be run in that ID NOW machine. GMH only began testing in-house on April 15. The test specimens that were taken there prior to April 15, if any, would have been tested at the Tamuning lab.
Likewise, the Commonwealth government was sending its test specimens to the Tamuning lab for testing prior to standing up its own test machine at the Commonwealth Health Care Corporation's laboratory in Saipan.
This means that wherever patients are tested, the specimen is placed into a vial with a special solution then transported to the Tamuning lab.
Abbott Laboratories, the manufacturer of the machine that runs the tests at the Tamuning lab, now says that placing the test specimens in that solution may lead to false negatives for the virus.
The company released the following statement on April 15:
"Some of our hospital and academic laboratory users have been validating our ID NOW COVID-19 rapid test (part of a lab's normal process) with the use of viral transport media (VTM) samples. VTM is a liquid solution used to store, preserve, and transport a virus sample. This method can reduce the sensitivity of the test through dilution, which can potentially lead to false negative results.
"ID NOW is designed for – and typically used within – urgent care clinics, physicians' office labs, emergency departments, and retail settings. This means that patient samples (swabs) are collected and tested directly on the ID NOW instrument, near the patient and without the use of VTM.
"In consultation with the FDA, we have instructed our customers not to use VTM for the ID NOW COVID-19 rapid test. The sample (swab) should be placed directly in the instrument for testing and not placed in any other media. We have updated our product information and are directly communicating with our customers."
According to a report by CNN:
"The company says customers should instead only place swabs with patient samples directly in the device. When that method is used, the test performs as "expected," an Abbott spokesperson said, adding that when the company learned about the issue it immediately notified its customers and the US Food and Drug Administration.
"Abbott has promoted the ID NOW test as a "point-of-care" test, meaning doctor's offices or clinics can collect samples from patients using swabs and quickly test the samples without having to transport them to specialized labs.
"Because the machine processes only one test at a time, labs might have used the transport media to store the test samples until they can be processed. Abbott's information on the test initially filed with the FDA listed a number of transport media that could be used with the test.
"Clinical pathologists and lab scientists at the Cleveland Clinic said the Abbott system has produced higher false negatives than other devices they tested."
NPR published a story within the past 24 hours discussing the Cleveland study:
"The fastest test being used to diagnose people infected with the coronavirus appears to be the least accurate test now in common use, according to new research obtained by NPR.
"Researchers at the Cleveland Clinic tested 239 specimens known to contain the coronavirus using five of the most commonly used coronavirus tests, including the Abbott ID NOW. The ID NOW has generated widespread excitement because it can produce results in less than 15 minutes.
"But the ID NOW only detected the virus in 85.2% of the samples, meaning it had a false-negative rate of 14.8 percent, according to Dr. Gary Procop, who heads COVID-19 testing at the Cleveland Clinic and led the study.
"'So that means if you had 100 patients that were positive, 15% of those patients would be falsely called negative. They'd be told that they're negative for COVID when they're really positive,' Procop told NPR in an interview. 'That's not too good.'
"Procop says a test should be at least 95% reliable.
"Abbott said any problems with the test could stem from samples being stored in a special solution known as viral transport media before being tested, instead of being inserted directly into the ID NOW testing machine. As a result, the company recently instructed all users to only test samples put directly into the machines."
State surgeon for COVID-19 Dr. Michael Cruz recommended that Gov. Lou Leon Guerrero not use any other type of test kit but the ones from Abbott Laboratory after Speaker Tina Muna Barnes tried to source other test kits from South Korea. The governor agreed with Dr. Cruz and said sourcing other test kits is a dead issue.