re: Louisiana COVID-19 - October 19, 2020 Update: +202 cases; +16 deaths; +3 hospitalized

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as of 10/13... state positivity rate is back above 5%

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Since 9/8 we have only had 2 days above 5%, how can our overall rate be above that?

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I think he's looking at the present positive & Test Volume Tab on the ldh site. It provides the positive percentage of the tests & cases to the actual date the test was taken; where as OP's grid is based on when the results are made public.

10/13 was 5.03%
10/14 was 5/13%
Nothing reported from 10/15 - 10/19

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I'm sure it's been said BUT what is the false positive %? Sabans 3 negative tests after the positive got me wondering again

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1-2% (98-99% specificity, for the PCR testing). That said, the impact of false positives on overall numbers is a function of the “true” positivity rate, since you have to also factor in the 20-40% false negative rate (60-80% sensitivity). The lower the “true” positive rate, the larger the impact of false positives. If the true positivity rate is >5% or so (among those being tested) then the false negatives would be expected to outweigh the false positives. Below 5%, false positives outweigh the false negatives.

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And are there other viruses that a person can have but be asymptomatic (other than HIV I can't think of any off hand)??

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Tons. Something like 50% of influenza infections are asymptomatic.

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Since 9/8 we have only had 2 days above 5%, how can our overall rate be above that?

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OP’s % positive calculation uses the number of reported cases (which excludes duplicate positive tests), divided by the total number of tests (which includes duplicate positive test).

That’s a big part of the reason for the difference in positivity rate between OP’s spreadsheet and LDH’s numbers.

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I'm wanting to know just how back they're screwing up these numbers.

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I know. We need to know cycle thresholds and probably type of tests used.

But regardless, a larger percentage of announced positives will be "false positives" when virus prevalence is low in the wild.

So...chances are a large chunk on the numbers we're seeing now are actually false positives.

F'ing Region 7 & 8 It's N. La's fault this go round... although seeing the number of tests go down and the rate of positivity go up, I just don't think that asymptomatic people are being tested as often as they were even a few weeks ago.

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553 in the hospital with 4.6 million people in the state. We are OVERWHELMED!!!

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But muh ICU capacity

Total cases by collection date on or after 10/5/2020 - 5,903, plus hospitalizations equals 6,456. The number I posted yesterday using the same methodology was 6,521. There are 65 fewer active cases today than yesterday, a decrease of 1.00%. 206 of the 202 new cases are from test dates during this time.

10/18/2020 10/19/2020 Change
274
722 722 0
546 546 0
604 604 0
481 481 0
348 348 0
262 262 0
240 241 1
667 667 0
582 607 25
498 511 13
465 503 38
225 273 48
57 94 37
0 44 44
0 0 0



5,971 5,903 206
550 553
6,521 6,456
340 (65)
5.501% -0.997%