COVID-19 Testing Saps Supplies Needed for Other Medical Tests
Wall Street Journal
The pandemic is shifting more supplies toward COVID-19 testing, creating shortages for other types of medical tests and prompting some labs to ration tests. Physicians and laboratories are encountering shortfalls of swabs, chemicals, and other equipment required to conduct and process tests. Approximately 30 percent of labs surveyed the week of Oct. 26 by the American Society for Microbiology (ASM) and the Association of Supply Chain Management said they were experiencing shortages of supplies to detect bacteria that cause strep throat, bronchitis, urinary tract, and other infections. Half of the 127 labs surveyed said they were short on supplies for common fungal infections as well as lung and blood diseases, according to the society. In addition, nearly 43 percent of labs surveyed said they had shortages of supplies to identify venereal infections, including chlamydia and gonorrhea. Patrick Godbey, a lab director in Georgia and president of the College of American Pathologists, and other laboratory directors say they expect the shortages to worsen in the coming months as both flu and COVID-19 cases rise. The University of North Carolina Medical Center has faced shortages of supplies needed to test for methicillin-resistant Staphylococcus aureus, according to Melissa Miller, the center's director of microbiology laboratories and an ASM committee chair. When supplies are scarce, the lab needs to use an older testing method that may be less accurate, she says.
First COVID Neutralizing Antibody Test Okayed by FDA
The Food and Drug Administration (FDA) said Friday it has granted an emergency use authorization (EUA) to the first commercial laboratory test to detect neutralizing antibodies against the novel coronavirus. Tim Stenzel, MD, PhD, director of the Office of In Vitro Diagnostics and Radiological Health in FDA's Center for Devices and Radiological Health, said: "The ability to detect neutralizing antibodies can help us gain additional insight into what the existence of antibodies may mean for patients as we continue the fight against COVID-19." Monoclonal antibodies that neutralize the increase in protein on SARS-CoV-2 are being examined as possible therapeutic agents for COVID-19 infection. Neutralizing antibody titers are a critical measure that vaccine researchers and regulators track as a marker to determine the immunogenicity of COVID-19 vaccine candidates. To date, FDA has granted EUAs to more than 50 serology tests for COVID-19 antibodies, which all detect binding antibodies rather than the neutralizing antibodies the new test detects. In both instances, the tests help to show whether an individual has had recent or prior infection with SARS-CoV-2. Stenzel cautioned, "Patients should not interpret results as telling them they are immune, or have any level of immunity, from the virus."
FDA: Potential for False Positive Results with Antigen Tests for Rapid Detection of SARS-CoV-2
FDA Letters to Health Care Providers
The Food and Drug Administration is cautioning health care providers and clinical laboratory staff that false positive results can occur with COVID-19 antigen tests. This includes instances where users do not adhere to the instructions for use of antigen tests. Antigen tests are typically indicated for individuals who are suspected of contracting COVID-19 by their health care provider within a certain number of days of the onset of symptoms. The agency noted it "is aware of reports of false positive results associated with antigen tests used in nursing homes and other settings and continues to monitor and evaluate these reports and other available information about device safety and performance." Health care providers and clinical laboratory staff should follow authorized test instructions, which are usually found in the package insert, as well as the Centers for Disease Control and Prevention's (CDC) recommended testing process, including follow-up testing with a molecular assay when appropriate. Processing multiple specimens in batch mode may make it more difficult to ensure appropriate incubation times for each specimen. It is also essential to reduce cross-contamination risks when testing patient specimens, such as by following CDC guidance to change gloves and cleaning work areas between specimen handling and processing. For positive results, in particular in low incidence counties, providers and lab staff should consider conducting confirmatory RT-PCR test within 48 hours.