Only 1,895 people have been tested for the novel coronavirus in the US, according to reporting by The Atlantic. That’s a shockingly low number: the UK has tested over 18,000 people, and South Korea is testing around 10,000 people a day.

There are over 200 people in the US with confirmed cases of COVID-19, the disease caused by the virus. But the number of people actually infected with the disease around the country is likely much higher. Researchers predict that there are hundreds of people in Washington state alone who have been infected in the past few weeks — the low number of cases is more a reflection of how little testing has been done than of the actual burden of disease.

Researchers predict there are hundreds of people in Washington alone who have been infected

In California, doctors and nurses are struggling to get patients with symptoms of the virus tested. California is able to perform the most tests per day — over 7,000 — of any state, The Atlantic found. Washington state is only able to test 1,000 samples a day. Oregon can only test 40 people per day. That’s despite Stephen Hahn, the commissioner of the Food and Drug Administration (FDA), promising that close to 1 million tests would be able to be performed by the end of this week. Even if that number were accurate, 1 million tests does not necessarily mean 1 million people tested. Labs are running two tests per patient, as ProPublica reporter Caroline Chen points out.

The Centers for Disease Control and Prevention (CDC) created its own test for the novel coronavirus at the start of the outbreak. The agency was quickly able to start testing samples at its central lab in Atlanta. However, testing capacity stalled out when they tried to get testing kits out to local labs: one part of the test kits was contaminated, and the labs weren’t able to validate that they worked. The FDA did not give state labs permission to create their own test, instead of relying on the CDC’s, until February 29th.

In addition, until last week, the CDC only recommended testing for people who had either traveled to a country where the virus was spreading or who had been in contact with someone who had a confirmed case of COVID-19. That’s why, for example, two patients in Washington state were not diagnosed with COVID-19 until a week after their death.

More testing is expected to go online soon, but experts say it still won’t be sufficient. Because the US hasn’t been testing more people, the outbreak in the country probably looks more containable than it actually is. Without data on where the virus is, it’s nearly impossible to beat back its spread.