Widespread testing for the coronavirus is key to safely reopening the country, but the U.S. has struggled for months to get to the level of testing many experts say we need — even as states and cities begin to loosen restrictions.

Part of the problem is that a test for the coronavirus is not a single device. Testing entails several different steps and requires supplies and pieces of equipment sourced from different places. These supplies have to make it from factories to testing sites where patients' samples can be collected and to the lab where tests are processed. Along the way, there can be shortages of various components, each one potentially creating a bottleneck.

The most common kind of test to check for an active coronavirus infection takes a sample from the back of your nose or throat. There are dozens of varieties of that test, but they all require one key element: the swab.

Even though health experts and governors were warning of swab shortages as early as February, the federal government took until late April to increase domestic production. That means that now, months into this crisis, we still need more of them.

In this video, we zero in on the swab, detailing what the federal government and private industry did and didn't do, and we break down why testing is so complicated in the first place.

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