Testing for the coronavirus (Covid-19) has been an ongoing issue due to the lack of testing resources. According to data from GlobalData’s Covid-19 Testing Data Dashboard, the cumulative number of people being tested for Covid-19 in the US has increased daily.
However, the positive test rate has declined, indicating that the US may be conducting sufficient testing for the disease in the population. In the US, there are currently two kinds of tests for Covid-19 – viral tests and antibody tests. A viral test can determine if a patient is currently infected, while an antibody test can determine whether a person had a previous infection. Testing for the disease is vital as it can identify people who have or have had the disease and show the scope and severity of the outbreak so appropriate health measures can be taken.
The World Health Organization (WHO) has estimated that a 10% positive test rate benchmark could be used as an indicator as to whether or not a community is conducting sufficient testing for the disease. Many countries have looked to South Korea as an example with its extensive Covid-19 testing. The daily positive test rates in South Korea have been steadily decreasing since early March.
Data from GlobalData has shown that the rates of positive Covid-19 tests in the US have been steadily declining since mid-April and have only recently fallen below the 10% WHO benchmark. In the US, positive test rates only started to drop below the WHO benchmark in early June. The decline in the rate of positive tests can be considered an indicator that the US has conducted sufficient testing. If the US continues to maintain
low positive test rates, it may indicate that the US should be able to make public health decisions based on the data such as the reopening of states.
Although the rate of positive tests is declining in the US, it does not mean that the number of cases will decline. When comparing the positive test rates in the US to South Korea, which conducted extensive testing early on during the pandemic, the US still has a long way to go.
There are a number of limitations to the testing data in the US. The data is compiled from a number of sources, including commercial, hospital, public health and the US Centers for Disease Control and Prevention (CDC) laboratories. Additionally, not all tests are reported to the CDC. Reporting methods also vary by state as some states may have submitted testing data that included both viral and antibody testing data, while others may have only submitted viral testing data.
The testing data has also changed over time as more testing locations have become available compared to earlier in the outbreak. Other countries also have issues with limitations to Covid-19 testing such as the availability of tests and having to ration tests by the severity of the disease.