But there are other tests, the US just didn't use them. South Korea has had tremendous success with testing.

> On Feb. 4, two weeks after South Korea reported its first coronavirus case, the government gave “emergency approval” for Seoul-based Kogene Biotech to move ahead with the test kits.

> Kogene currently exports test kits for the novel virus to 35 countries in Asia, Europe and the Middle East.

https://www.washingtonpost.com/world/asia_pacific/coronaviru...

> Researchers say a viral test is relatively easy to develop. Rather, scientists say, the chasm between the testing haves and have-nots reflects politics, public health strategies and, in some cases, blunders.

> South Korea opened nearly 600 testing clinics, including dozens of drive-through stations. More than 250,000 people have been tested

https://www.nytimes.com/2020/03/20/world/europe/coronavirus-...

jupp0r is correct; this is a real problem for a disease that is so contagious.

Lets say the covid-19 (real) prevalence is 0.1% in the US now. That means 10k infected people for every 10 Million people. If 10M take the test, 97.90 % sensitivity means, of the 10k (true) infected people, 210 will show up as negative. If these people go out and "mingle", there is potential for the infection to pick up again.

It is probably useful for getting population statistics and directing higher level actions, or even at some point overquarantining people based on positives and false positives, but people that get a false sense of security are a risk. There was an article about a village leader who tested negative and had 200 villagers come to congratulate him, then he tested positive on a subsequent test.