As of Sunday, 1,707 Americans had been tested for the coronavirus, according to the Centers for Disease Control and Prevention (CDC). South Korea, by contrast, has tested more than 189,000 people. The two countries announced their first coronavirus cases on the same day.  
In the US, test-kit shortages have hampered health authorities’ ability to get a clear sense of how many Americans are infected. Compared to many other countries impacted by the coronavirus, in fact, the US has done the fewest COVID-19 tests per capita.
South Korea’s testing total so far, when broken down into number of tests performed per million citizens, seems to be about 700 times higher than the US’.
How many people have been tested per capita in 8 countries
Skye Gould/Business Insider
Because China has not published national data about its coronavirus testing, Guangdong province is used here for purposes of comparison.
“The infectious-disease community and the public-health community desire to do much more testing than is currently feasible,” William Schaffner, an infectious-disease specialist at the Vanderbilt University School of Medicine in Tennessee, told Business Insider on February 26.
“Other countries are testing much more broadly than we are,” he added. “We are trotting along while they’re racing along.”
It’s likely the US has done more tests than the CDC’s reported figure suggests, since the agency isn’t tallying tests performed at state and private labs in the last week. US Food and Drug Administration commissioner Stephen Hahn said on Friday that the US had actually conducted 5,861 coronavirus tests, CNN reported. That number did not include tests conducted at private and commercial labs, Hahn added.
People wear face masks as a precaution against coronavirus in the New York subway, March 3, 2020.
Tayfun Coskun/Anadolu Agency via Getty Images
But even that higher number of tests per capita would still put the US behind the other seven countries listed above, with 18 tests per million people.
Testing influences what we know about the coronavirus’ death rate
Without adequate testing, it’s challenging for US public-health officials to grasp the scope of the outbreak’s spread and determine how dangerous it is. More widespread testing could impact the disease’s known death rate, a basic calculation that divides the number of reported deaths by the total number of confirmed cases.
The US has one of the highest death rates in the world — about 3.6% as of Monday — but that’s likely because so few mild cases have been counted.
Because testing capacity has been limited in the US, the CDC initially held stringent standards for who qualified. Until last week, the agency tested only people who had recent exposure to a confirmed patient, had traveled to a country with an outbreak, or required hospitalization.
So the US still probably has not tested or provided diagnoses to some patients with mild cases. Currently, 22 Americans have died out of about 600 cases. 
A healthcare worker prepares to transport a patient on a stretcher into an ambulance at Life Care Center of Kirkland, Washington on February 29, 2020.
David Ryder/Getty Images
South Korea, which has the third-highest number of cases outside China, has a death rate iof just o.7% — 50 people have died out of 7,478 cases. 
However, outbreaks in both countries continue to evolve, and many patients are still hospitalized, so their conditions could change with time.
A disease’s death rate is also different from its mortality rate — the latter is the number of deaths out of the number of people in an at-risk population. The death rate is not a reflection of the likelihood that any given person will die if infected.
Aria Bendix contributed reporting.