How U.S. can improve COVID-19 testing

Every untested person could be spreading virus unknowingly.

For many people in the U.S., getting tested for COVID-19 is a struggle. In Arizona, testing sites have seen lines of hundreds of cars stretching over a mile. In Texas and Florida, some people were waiting for five hours for free testing.

The inconvenience of these long waits alone discourages many people from getting tested. With the surge in cases, many public testing sites have been reaching maximum capacity within hours of opening, leaving many people unable to get tested for days. Those who do get tested often face a weeklong wait to get their test results.

Every person who isn’t tested could be spreading COVID-19 unknowingly. These overstretched testing programs are a weak link in the U.S. pandemic response.

The key to overcoming this pandemic is to slow transmission of the virus by preventing contagious people from infecting others. A widespread quarantine would accomplish this but is economically and socially burdensome. Testing offers a way to identify contagious people so they can be isolated to prevent the spread of the disease. This is especially important for COVID19 because an estimated 40% or more of all people infected with SARS-CoV-2 have few or no symptoms, so testing is the only way to identify them.

Some states are doing much better than others. But as a whole, the U.S. is falling far short of the amount of testing needed to control the pandemic. now, nowhere in the U.S. comes close to meeting surging demand for testing.

Texas, patients are supposed to get results through an online portal in three to five days, but many labs have been taking seven to nine days to return results. These long delays mean people face a much higher burden of quarantining while waiting for results.

All of these challenges make it clear that Texas is simply not testing enough people to keep the spread of COVID-19 in check.

To gauge the success of COVID-19 testing programs, epidemiologists use a measure called test positivity. This is simply the percentage of tests that come back positive. The lower the test positivity, the better, because that means very few cases are going undetected. A high test-positivity rate is usually a sign that only the sickest people are getting tested and many cases are being missed.

The World Health Organization guidelines say that if more than 1 out of 20 COVID19 tests comes back positive — a test positivity of more than 5% — this is an indication that a lot of cases are not diagnosed and the epidemic is not under control. Texas currently has a test-positivity of around 16%, which means that a lot of infected people are not getting tested and may be unknowingly spreading the disease. access to testing has resulted in one of the highest per capita testing rates in the country, at over 20,000 tests per 100,000 people, and a test-positivity rate of around 4%. New Mexico’s testing program is diagnosing a relatively high proportion of cases despite the state experiencing a recent surge.

Long lines, wait times and limited capacity are becoming more common as cases surge, but the foundation of a strong testing program has helped the state cope with the increase in cases.

DAVID J. PHILLIP / ASSOCIATED PRESS America’s pre-pandemic infectious disease testing capabilities cannot meet demand. Congress, the federal government and local governments can do three things to help.