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HomeCOVID-19COVID test positivity is not a meaningful statistic because not all negatives are reported

COVID test positivity is not a meaningful statistic because not all negatives are reported

July 7, 2020

BY JENNIFER CABRERA

Updated with a link to Florida’s reporting rule.

The percentage of positive COVID tests has increased dramatically in Alachua County and in Florida, and we now have evidence that this percentage is misleading at best.

The percentage of positive tests has been used throughout the pandemic as a measurement of community spread, with most public health authorities agreeing that it is best to keep that rate below 10% (with 5% being even better).

Alachua County’s positivity rate hovered around 1% from May 9 to June 10, and it suddenly spiked on June 11 when the migrant farmworker cluster (with 90% positivity) was reported.

Also around that time, the University of Florida stepped up its employee testing in preparation for their return to campus, and we also know that the university and its hospitals started testing athletes and hospital admissions, at least. Other employers are probably also testing employees. A quick scan of the labs reporting results to the state (starting on page 24) shows that a number of labs and hospitals are reporting 100% positive tests–i.e., they are not reporting the negatives.

It looks like North Florida Regional and Shands are reporting at least some negatives, but we now know that UF is not reporting negatives in employee testing to the state. By law, all test results by physicians, hospitals, and laboratories are required to be reported to the state, but the list of labs reporting 100% positives indicates that’s not happening–or perhaps tests performed by an employer are not covered by the order.

We know that not all of the local negatives are being reported because UF reports the results of its employee testing here; we log that number on a spreadsheet when it changes, and the number of total tests increased by 3,527 from July 4 to today (with only one positive test). Over that same period, the state reported an increase of 1,423 tests (with 195 positive tests). [Editor’s note: The total number of tests reported by UF mysteriously dropped by 3,186 a day after this article was published.]

That means that the official positivity rate for those three days was 13.7%, but when you add the unreported negatives from UF, it becomes 3.9% (and that’s only adding the negatives we know about; there are almost certainly others). That paints a very different picture of community spread.

If negative tests aren’t reported, they aren’t added to the total number of tests. That makes the reported positivity rate higher than the actual positive percentage of all tests performed. This can easily be seen when you look at the hospitals reporting 100% positive tests. If they reported 50 positives with 100% positive tests, for example, the number of tests reported to the state is 50. If they did 500 tests to get those 50 positives, 450 tests were not reported to the state and were not added to the total number of tests reported by the state.

  • Thank you so much for all the time and energy you devote to uncovering and reporting the truth about what’s going on in our community.

    • are you really that challenged in math to figure out how many negative cases there are when they give you posirices and the amount of tests given?

  • I also wonder why there is never a down turn in cases. Do they remove the ones that have recovered at all?

  • SUSPICIOUS OF CV-19 REPORTS?…MANIPULATION OF DATA RESULTS IN FAKE POSITIVE COVID-19 CASES. — New definitions for designating Covid-19 cases have been distributed by the Department of State Health Services in Texas. Prior to the new case status definition a person must have a positive result for Covid-19. This result was reported as only one identified positive Covid-19 “case”. — In the new case definition contact tracing is included to report other people who were in contact with the one person who tested positive. This new counting method is a game of GUILTY BY ASSOCIATION that skyrockets reported positive cases of Covid-19 by adding “probable” cases (who may have never been tested) to the total reported case count. In this video, the one person who tested positive mushroomed to a total of 17 reported cases of covid-19.
    https://theconservativetreehouse.com/2020/07/02/explosive-about-all-these-new-positive-covid-cases-state-health-departments-manipulating-data-changing-definitions/?like_comment=8429552

    • Are they using the Covid test for other reasons not stated like collecting citizens DNA
      To add to the DNA database to identify us? Would they
      Tell us if they were?

  • […] COVID test positivity is not a meaningful statistic because not all negatives are reported – Alachua Chronicle “If negative tests aren’t reported, they aren’t added to the total number of tests. That makes the reported positivity rate higher than the actual positive percentage of all tests performed.” […]

  • For this to be an article for for people to even comment on this and not know how to figure out what the negative rate is just baffles me. You subtract the positive by the number of tests given . Im just absolutely blown away that no one who wrote the article or wasted their time commenting could figure this out

    • The article explains exactly how the positive rate is skewed by the lack of negative reports. The simplicity of subtracting total positives by the number of tests given does not take this into consideration. 50 positives in 500 tests reported may simply mean that there was a 10% positivity rate with 450 negatives, but if there are another unreported 500 negative tests, then that positivity rate drops to 5%. Also, non-positive tests can also mean they were inconclusive, which also will affect negative numbers.

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