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  • One of the best ways to figure out how far a virus like Covid-19 has spread in a community is to test for it.
  • In the US, massive federal delays rolling out Covid-19 testing have led to a situation where it's hard to track where new cases may be spreading in real time.
  • Here's how a coronavirus swab-the-nose-and-throat test works, why it takes so long to produce results, and why it doesn't always turn up positive, even if a person has (or had) Covid-19.
  • For more stories, go to Business Insider's home page.

Do I have the coronavirus?

That seemingly simple question is proving exceedingly hard to answer definitively. In many places around the US, it's exceedingly difficult to even get tested for Covid-19, the disease caused by the coronavirus.

With the virus now spreading across all 50 states, there are far more people in the US who want coronavirus tests than can get them, and those who get tested do wait days for their results. More than 1.2 million people nationwide have gotten a Covid-19 test, and about 17% of those test results have come back positive, according to the US Centers for Disease Control and Prevention.

For those who do manage to get tested, the test itself is also painful.

A test for Covid-19 starts by reaching deep inside a person's nose and throat to extract sputum - the gunk that gets ejected through coughing, sneezing, spitting, and even singing. That throat gunk, in turn, can be tested for the presence of some of the coronavirus' tell-tale genes.

But, if a person's infection isn't living in the spot where they are swabbed, their infection isn't caught at the right moment, or their sample isn't collected properly, their test could still come back negative.

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