The importance of test verification in public health laboratories

by Gynene Sullivan, manager, Communications, APHL

With the changes to regulations regarding the development and dissemination of laboratory tests, there have been a myriad of companies who have begun marketing COVID-19 tests to public and private laboratories. While it is important to provide testing wherever and whenever necessary during the pandemic, it is also critical that approved tests are verified by the laboratory that intends to use them. This step is important in assuring that the test and the results are accurate and reliable.

Tests are Performed to a Universal Standard
Because public health laboratory facilities and equipment vary across the country, having standard guidelines to follow when performing a test ensures that the testing process is good, the data to be shared is on par with other laboratories and the laboratorian performing the test has the correct educational qualifications and is competent at performing the test. The most common standard followed by public health laboratories is the Clinical Laboratory Improvement Amendments of 1988 (CLIA). The US Food and Drug Administration (FDA) also regulates the release of tests, and there are many levels of FDA approvals. Even though securing these approvals takes time, it ensures that highly-complex testing, such as molecular diagnostics, or laboratory-developed tests are produced and used across all laboratories.

When the FDA issues an Emergency Use Authorization (EUA), it allows FDA to help strengthen the nation’s public health protections against threats by facilitating the availability and use of medical countermeasures needed during public health emergencies. In the case of COVID-19, manufacturers submit a “Letter of Intent” to FDA to let them know that they will begin distributing testing kits and equipment, and that they have validation for said tests. During this public health emergency, it is necessary for manufacturers to provide their validation data within 15 days of filing their Letter of Intent, so that the appropriate officials can review that data to ensure that tests were performed correctly and under the conditions specified by the testing instructions.

Tests Need Interpretation
Laboratory testing is a multi-step process, one that begins with sample collection and ends with reportable results. Laboratory scientists have the education and training to determine whether a test is being affected by variables such as device performance and sensitivity, whether a test needs to be performed again due to a false positive and if the integrity of a sample has been compromised. A test that is administered at home or at point-of-care may be highly variable. For example, a negative result may be due to of timing of sample collection, since it takes 3-7 days before an individual infected with SARS-CoV-2 produces sufficient antibodies for detection. Another situation is if a person is infected with a different strain of coronavirus, the test may produce a false positive for COVID-19 and, without a trained laboratorian to interpret the result, unnecessary treatment or quarantining may result.