Thread by @jimbuctwit

Let’s discuss test positivity rate (TPR) again.

Review: TPR is the % of total RESULTS (+ & -) that are positive. I chose those words carefully as nowadays a batch of results presented one day might represent tests conducted over many preceding days.

It’s crude metric.

THREAD…

TPR is influenced by testing practice in an area of interest.

For example, if tests only done on people with symptoms there is a high chance many will be positive. TPR will be high.

If tests only done as pre-op screening in people likely to be negative, TPR will be low.

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If tests are used for a blend of these examples TPR might produce an OK “value”.

Experts say a TPR value consistently AT OR BELOW 5% indicates a sufficient # of people in a community are being tested. BUT for # to be valuable a BROAD SAMPLING of the community is necessary.

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This doesn’t simply mean open testing to anyone who wants a test.

Best use should include aggressive testing of CONTACTS of test-positive people, frequent testing of “front line” workers, nursing home staff, health care workers, etc.

They are members of the community.

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With a proper data set (broad range of community being tested) TPR can be very useful in guiding local policy and behavior.

South Dakota community officials and public should PRESS HARD on @SDDOH to describe the testing strategy in use and to open up testing to more people.

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If @SDDOH cannot or will not speak to this in a direct and clear way one can only conclude that there is something afoul within the Department. They have a lot on their plate so I’m hoping there’s a benign explanation. I suspect capacity has been exaggerated, but why?

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CONCLUSION:

More and more diffuse testing will provide a useful TPR which may help guide statewide, and more importantly, local policy and behavior. Let’s keep pushing for more testing. If DoH will not open up testing let’s hear why.