Washington state bore the brunt of the US' testing problems. It now has a third of all coronavirus deaths in the country - here's a timeline of what went wrong.

• The Washington State Public Health Laboratory didn't start testing for the coronavirus until February 28.
• By then, the virus had likely been spreading throughout the state for more than six weeks.
• Washington now has a third of all coronavirus deaths in the US - which is partially a product of the country's testing delays and snafus.
• For the latest coronavirus case total and death toll, see Business Insider's live updates here.
• Visit Business Insider's homepage for more stories.

It all started in Washington - the state reported the US' first coronavirus case, the first death, and one of the first outbreaks on US soil.

In mid-January, as federal health officials were reassuring US citizens that the risk to the general public was low, the coronavirus was already spreading through the greater Seattle area. Researchers from the Seattle Flu Study determined that around 570 people in Seattle had been infected by March 1.

But a nationwide lag in producing and distributing working coronavirus tests prevented most of those cases from being detected early by state health officials. As a result, Washington, more than any other state, has struggled to isolate and trace infected patients.

The delays are likely part of the reason the state landed in the position it's in now - Washington has more than a third of all coronavirus deaths in the US and more than 1,500 infected patients. Here's a timeline of what went wrong.

Washington's first case

Two months ago, a 35-year-old man entered an urgent care clinic in Snohomish County, Washington with a fever and a cough. He sat in the waiting room for 20 minutes with a mask over his face. During his examination, he told his healthcare provider that he had returned a few days earlier from a trip to Wuhan, China - the origin site of the coronavirus pandemic.

The man was the US' first case of COVID-19. His diagnosis was confirmed by a Centers for Disease Control and Prevention test, the details of which were shared with the public on January 24. At that time, no state laboratories could legally perform the CDC test, so hospitals had to send patients' samples to CDC headquarters in Atlanta.

By the time the man was diagnosed on January 20, the virus had likely been circulating in Washington for several days, researchers from the Seattle Flu Study determined. But another five-plus weeks would pass before the Washington State Public Health Laboratory was able to test patients using the CDC kit.

A holdup on CDC kits

The test used to diagnose the first coronavirus patient, a polymerase chain reaction (PCR) test, compares the genome of the coronavirus to samples taken from a throat swab or a saliva sample. The same type of test is commonly used to diagnose tuberculosis, influenza, and measles. The Food and Drug Administration approved the CDC's PCR tests for emergency use on February 4. Two days later, the CDC began shipping the tests to state public health labs across the country.

The Washington state lab received its first shipment on February 7. The package contained enough materials to test 850 samples. But one of the chemicals, or reagents, in the tests turned out to be faulty, causing the lab to get inconclusive results.

The majority of state labs across the country identified the same problem.

They flagged the issue to the CDC, which passed the information along to the FDA on February 10. The CDC considered sending a new batch of reagents to state labs, which would allow testing to begin in a few days, the New Yorker recently reported.

But instead, the FDA eventually gave all 50 state labs permission to use the original tests without one reagent that was to blame for the inconclusive results. That green light didn't come until February 26 - more than two weeks after the problem was reported. That same day, the Washington state lab received a second shipment of tests with the capacity to test another 850 samples.

From there, the lab had to perform a quality check on the tests - a process that typically takes around 48 hours.

That meant the Washington state lab did not start performing tests until February 28. A day after the state testing started, Washington reported its first death.

Labs missed a major outbreak at a nursing home

Public-health officials were also late to spot an outbreak at the Life Care Center nursing home in Kirkland, Washington, perhaps because of limited testing capacity or simply a failure to identify sick people as coronavirus patients.

The Washington Post reported that the facility's first COVID-19 patient was taken to the hospital on February 19. A spokesman for the Life Care Center told The Post that the facility had mistakenly flagged the virus as an outbreak of influenza. On February 27, the facility reported an "increase in respiratory illness" to King County officials.

The center's first two cases weren't diagnosed until February 29, the day after the Washington state lab began testing.

"If we had the ability to test earlier, I'm sure we would have identified patients earlier," King County public health officer Jeffrey Duchin said on a press call on February 29.

As of Monday, at least 76 residents and employees at the Life Care Center had been infected and another 29 had died, The Washington Post reported.

King County is now the area with the highest number of reported cases in Washington.

As the virus spread, academic labs couldn't test

A day after the Life Care Center's first two cases were diagnosed, the FDA started permitting certified academic hospital labs to perform their own clinical COVID-19 tests. Before that, only state labs had been allowed.

"One of the things that's frustrating is that the first month the CDC gets all the samples, makes a test, and then subsequently only distributes it to the state public health labs. They do not distribute it to clinical labs," Alex Greninger, assistant director of the University of Washington Medicine Clinical Virology Laboratory, told Business Insider. "So the people who perform 99.9% of the testing [in the US] are not able to bring our volume and our machinery and our robots to bear on this problem."

Greninger's lab developed its own COVID-19 test in mid-January in anticipation that it might soon be called upon to diagnose patients.

The lab is part of the Clinical Laboratory Improvement Amendments (CLIA) program, which verifies that private and academic labs meet federal standards for diagnostic testing. CLIA-certified labs are essentially the government's secondary line of defense for detecting an outbreak.

As a CLIA-certified lab, the University of Washington was legally permitted to test for COVID-19 using specimens that had been sent there for other purposes, like a flu test. So Greninger said his lab started respiratory samples for COVID-19 under this protocol.

For about six weeks, the team didn't find any cases.

"Every time we flipped the coin, it came up negative," Greninger said.

Without a positive case, it couldn't verify that its test actually worked.

But finally, on February 28, Greninger received a swab from one of the first diagnosed patients in Washington.

"It wasn't until we had our first positive on the 28th that we were like, 'Hey this test works,'" he said. "By that time, we had probably over 1,000 cases in the Seattle area."

The following day, the FDA started allowing CLIA-certified labs to diagnose COVID-19 patients. Greninger's lab began testing on March 2, about 48 hours after the rule came through.

The number of reported cases in Washington and the US overall have skyrocketed since then. The number of positive cases went from less than 20 on March 2 to more than 1,300 on Thursday. As of Wednesday afternoon, more than 17,000 people had been tested for the virus across Washington.

Greninger said his lab now administers 1,800 to 2,000 tests per day and diagnoses more than 100 to 150 patients each day in the Seattle area. Even then, he said, it's difficult to keep up with testing demand.

"That's actually one of the big choke points is just the physical processing of the samples," he said. "We have to sample every 40 seconds."

The virus is still spreading in Washington

On Sunday, Washington became the first state to order an emergency shutdown, which included closing all restaurants and bars and limiting public gathering to 50 people or less. Greninger said these types of measures were the first indication that the virus was actually being taken seriously in the US.

"It would have been helpful to know that it was spreading here," he said. "Unfortunately it took real morbidity and mortality. It took spread in Europe. It took death - I don't know another way to say it - to really invoke social distancing."

A day after the emergency shutdown, Trevor Bedford, a researcher at the Seattle Flu Study, estimated that around 90% of the viruses sampled from Washington could be traced to a single case from China in January. Based on this, he estimated that local transmission was driving more new cases in Washington state than transmission from infected travelers who had recently entered the US.

"It looks like there was more community transmission here in North Seattle," Greninger added. "It just wasn't being tested for."