How many tests for COVID-19 are being performed around the world?
Why is testing important?
We want to know the total number of people infected with COVID-19. To know this, it is necessary to have widespread testing.
When testing is too low we do not have a clear picture of what’s going on.
Testing is crucial as it allows the infected person to avoid infecting others and to quickly receive the care they need. And it is crucial for all of us to understand the prevalence of the disease, to understand how the disease evolves, and to allow us to take evidence-based decisions for counter measures that slow down the spread of the disease.1
This last point is very important: Testing is crucial to lower the rate of infection. When infected people do not know that they are infected, they might not stay at home – thereby running the risk of infecting others.
Unfortunately, there are two important reasons why testing is still low in many countries affected by COVID-19.
First, some people who are infected with COVID-19 have mild symptoms and therefore do not go to get checked (we explain what is known about the symptoms here and also discuss how many suffer from severe and critical symptoms).
The second reason is that in many places the capacity for COVID-19 testing is low.
How are COVID-19 tests done?
The most common diagnostic tests for COVID-19 are the so-called “PCR tests” that use swabbed samples from a patient’s nose and throat.
The first PCR tests were developed within two weeks of the disease being identified, and are currently part of the protocol recommended by the WHO.2
Here you can find an explainer video on how the tests for coronavirus disease work.
What information about test coverage do we currently have?
Ideally, we would want to know how many people in the world are being tested for COVID-19 every day, and how the available tests are being allocated.
Unfortunately there is no centralized database by the WHO on COVID-19 testing and many countries in the world currently do not publish official reports on tests performed.
Several countries however do publish aggregate estimates on the total number of tests performed. These reports are published across individual websites, statistical reports and press releases – often in multiple languages and updated with different periodicity.
Because a global overview was not available, we at Our World in Data brought together a large number of data sources from individual national reports.
Below we show the most recent data as of 13 March 2020, 09.00 GMT. We will do our best to expand and update these estimates regularly.3
Current COVID-19 tests coverage estimates
The two charts here show the most recent official estimates of tests we have been able to find as of 13 March 2020, 09.00 GMT.
Note that the estimates refer to different dates for each country, as indicated in the brackets.
The first chart shows the total number of tests up to the specified date.
The second chart shows the number of tests relative to the size of the population: it is the number of total COVID-19 tests per million people.
The available data shows that South Korea has done many more tests than any other country. This suggests that the number of confirmed cases in Korea is closer to the total number of cases than in other countries.
It is therefore particularly encouraging to see that the number of daily confirmed cases in South Korea has decreased – here you find our chart that shows the decline of confirmed new cases in South Korea.
The US, on the other hand, has experienced big problems rolling out their testing strategy and according to the US Centers for Disease Control and Prevention, only a total number of 13,624 samples had been tested by 12 March, 2020. The total number of tests conducted in South Korea up to the same date was nearly 18-times larger.
The low test coverage of the US is even starker if we look relative to the large population of the country. We see many smaller countries have been able to conduct more tests per million people.
[NB. We provide two estimates for the US. The estimate labelled “US – CDC samples tested” is from the Centers for Disease Control and Prevention, and refers to the number of tests conducted, not the number of individuals tested. The COVID Tracking Project tracks the cumulative number of people tested in the US by tallying individual state reporting. We report these figures under the label “US – COVID Tracking Project”]
The fact that South Korea has managed to expand testing so quickly shows that it is possible. Because testing is crucial it is important that in the coming days other countries follow.
Country by country estimates and sources
We list estimates country by country, including exact dates and links to the underlying source, in a companion page here.