Testing backlogs at US private laboratories have ballooned

From the article:

Though the problem is national in scope, California is its known epicenter. Over the past week, the most populous state in the union—where the country’s first case of community transmission was identified, in late February—has managed to complete an average of only 2,136 tests each day, far fewer than other similarly populous states, according to our tracking data. Yet California also reports that more than 57,400 people have pending test results. Tens of thousands of Californians have been swabbed for the virus, but their samples have not yet been examined in a lab.

[...] the numbers suggest that California will take weeks to work through the backlog.

[...] Within the clinical-testing world, it is an open secret that Quest Diagnostics—one of the industry’s two big players, along with Labcorp—has struggled to scale up its operations in California. And yet, Quest has continued to accept specimens from across the country, leading to a huge backlog of tests at the company’s facility in San Juan Capistrano.

This failure accounts for at least some of the tens of thousands of pending tests reflected in the state’s reported numbers. According to experts, it isn’t Quest’s fault that the company has so far been unable to meet the technical challenge of testing thousands of people every day. Setting up such “high throughput” operations is difficult. But Quest failed to come to terms with its ongoing problems, and it continued to accept specimens—and generate revenue—when other laboratories could have done some of the tests faster.

[...]

Quest faces two major problems in dealing with its backlog, whatever its size. First, on March 9, Quest started using a labor-intensive, laboratory-developed test, Bost said. Then, sometime after March 13, it switched to using a highly automated, high-throughput test created by the Swiss manufacturer Roche.* The problem is that specimens collected for the first type of test cannot be used in the new machinery—and many of the early samples were meant for the laboratory-developed test. It does not matter how many high-speed Roche machines Quest is using now: They cannot be brought to bear on those other samples. This could be one reason for the existing backlog, though Bost told us she could not say so for sure.

The second problem is that the federal government has asked that certain tests—such as those for hospitalized people and frontline health workers—be prioritized. But those early samples probably do not have the metadata attached to them that would allow Quest to move them higher up in the queue. So samples meant for the slower test must simply be run on a first in, first out basis.