Variability in states’ testing numbers: It’s not that simple

By Gynene Sullivan, manager, communications, APHL

Throughout the COVID-19 response, there has been a lot of discussion about the fact that laboratory testing numbers across the United States have been varied, and this is nowhere more evident than our public health laboratories. But this concept is more than numbers; it resides in a variety of factors.

Being Able to Prioritize
It is incorrect to assume that some states are doing things right, and other states are not performing tests or testing incorrectly. If a state has fewer issues with backlogs, they may have been more successful in prioritizing surge testing, or have been recognized as a hotspot, which leads them to be prioritized for receipt of supplies. This leads to other states not receiving supplies or equipment and, therefore, when surge testing is needed they are less able to respond. If a public health laboratory is able to perform verified testing on equipment that is usually reserved for other testing, they get the advantage of having a backup system in case they run out of supplies for the main testing protocol.

Not All Tests Are Created Equal
There are many different tests that are performed in order to get results during an epidemic. Public health laboratories have a standard operating procedure for each test that is unique to their laboratory, based on their equipment, staff training and certifications. They also follow a meticulous series of protocols to ensure that tests are performed safely and correctly, and that they are not reporting false positives or false negatives. In a situation like this, public health laboratories are using all the tools available in their testing arsenal, while maintaining rigorous scientific processes to get the right results.

Allocation of Needed Resources
There are currently public health system-wide issues that point to supply shortages, equipment shortages and shortages of qualified staff. These tests are deemed to be highly complex that require scientific staff who have been trained to process and analyze them, require specific equipment to perform the testing and require specific materials to ensure the integrity of samples. Even though a state may be able to perform testing 24/7, they would have to suspend any testing if they run out of supplies such as test kits and reagents. And this would result in a cascade effect of non-testing and non-reporting.

Laboratory Capacity
The reality is different states have different capacity to stand up surge testing in a public health emergency. While public health laboratories have preparedness plans to respond to just about anything, no laboratory can be entirely prepared for a global pandemic. If states have the ability to convert to 24/7 surge testing, other requests such as newborn screening, food testing, water testing or STD testing may be deprioritized.