Thread by @COVID19Tracking

The US has now completed tests on over 1 million people: 1,048,971 to be exact.

It's a milestone.

But/and our daily number of completed tests does not appear to be rising anymore.

For full details, see: covidtracking.com

One reason is supply constraints, which are hard to pin down, but definitely a real factor. Also, many labs are taking up to a week to return tests, so our quantitative view here is likely considerably lagging the underlying reality.

There are also clear *demand* constraints as testing criteria remain quite strict. We are still getting reports from all over of people who have been able unable to get tested despite having a good reason to do so.

Also: testing doesn't only help people track the outbreak. It also matters for patient care, and one of the more troubling trends right now is how long it takes to *rule people out* through negative test results. That causes hospitals to burn through PPE.

If you've been following this account, you know we've been tracking The California Situation. The state is completing barely 2k tests a day but has a 57k test backlog. What's going on?

We finally have some answers on what's been going on in California. The short version: as demand exploded in the week after March 9, the key private lab simply could not keep up.

theatlantic.com/health/archive…

latimes.com/business/story…

In @TheAtlantic story, we tried to get at why this is important. Long turnaround times cause hospitals to burn precious PPE for staff.

theatlantic.com/health/archive…