The US government has come under fire for its response to the coronavirus - particularly because it has tested far fewer people than other affected countries.
On Thursday, the top health official for infectious diseases admitted that the testing system was "currently failing", and that the US was not able to supply tests "easily, the way people in other countries are doing it".
US President Donald Trump has now declared a national emergency to help handle the growing outbreak of coronavirus.
How many people have been tested in the US?
The short answer is no-one knows for sure - not even the government.
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Both Vice-President Mike Pence and Health and Human Services Secretary Alex Azar have been unable to confirm how many Americans have been tested.
This is because some tests were being conducted by private laboratories and hospitals that have not been reporting in to the Centers for Disease Control and Prevention (CDC).
"We don't have a centralised data registry tracking this the way we should," says Prof Howard Forman, a public health expert at Yale University. "We should learn from this experience - having a centralised registry to keep track, with information flowing from labs to state and then federal governments, is critical."
One thing that is widely accepted however, is that US testing has lagged far behind that of other countries.
One project by The Atlantic estimates that about 14,000 people have been tested in the US so far. Meanwhile, US lawmakers said on Thursday that fewer than 10,000 people had been tested.
By contrast, countries with far smaller populations have conducted more tests. South Korea has tested more than 210,000 people, while the UK has tested 32,771 people.
During a conference, Prof Pardis Sabeti, an expert in infectious disease, estimated that South Korea was testing "700 times more people per capita than the US".
Prof Forman says the US response has been inadequate.
"Certainly at a federal level, we've not done a good job at all," he says.
"In an ideal world we'd be emulating South Korea - with parking lot and drive-through testing" which prevents sick people waiting in emergency rooms and infecting others, he adds. BBC