Questionable value of indiscriminate testing

Long waits for test results.

I have been skeptical of the emphasis placed on testing since the pandemic started. Now, we are simply testing too many people. People are being tested often for political reasons, as testing a lot of people you have no reason to believe are infected creates the illusion of a low infection rate.

But the real problem is that SOME patients can benefit from being tested, and the deluge of needless tests is causing their results to be delayed until they are no longer useful.

This is not a new problem. When I treated patients with severe dental infections, the “standard of care” was to do a ‘gram stain’ and a ‘culture and sensitivity test’ to determine which antibiotics were appropriate. The tests took 4 to 5 days, cost even then $300 to $400 dollars to the patient, and were utterly useless since dental infections are almost always mixed cultures. But, if I didn’t run them, and things went bad, I could be successfully sued. Of course, I couldn’t leave a patient in agony for 5 days waiting on the test, so I treated with a broad spectrum penicillin, and if there wasn’t rapid improvement, switch them to Clindamycin, invariably, the infection would have been dealt with before the useless results came back. But to protect myself from lawyers, I used to run the  tests anyway, until I realized that if I got the patient to refuse the test I was covered. But it still wasted a lot of my time explaining that to the patient, who just wanted the pain to stop.

The point being that the ONLY legitimate reason to run a test at the patient’s expense is if it is useful in the patient’s treatment. If a test is to be run for gather epidemiologic data gathering, it should be at the government’s expense and processed at a lower priority than tests being run to guide treatment.

We just can’t mix the needed tests with data gathering testing.

20 thoughts on “Questionable value of indiscriminate testing

  1. Testing is still inadequate and often pointless with days or weeks to get results. We are handling this pandemic terribly. At the least we should have engaged university labs throughout the country to help with testing. A test of the contagion is no good if the wait is long.

    If we were serious about this crisis, and I don’t think we are judging by the administration’s actions, anybody should be able to walk into any CVS or Walmart or local clinics and get tested right away with results in less than 24 hours or even 1 hour. And they should be free or very low cost.

    We are 5 months into our worst health crisis in a century and we still can’t contain it.

    Plus a decent percentage of people don’t give a crap, believe in conspiracies, demand freedom to infect others. Trump has hardly mentioned the crisis like it is going to disappear on its own. Remember the “hot weather” solution. Well we are in a heat wave and the infections are raging.

    What is the administration doing besides planning the next rally?

    Liked by 1 person

    1. I don’t think you understand what is involved in testing.

      The test swabs have to be transported to the labs, and the swabs manually sampled into a cell, That cell goes into an automated machine that runs the tests.

      Those machines, loaded with other reagents, do other kinds of tests as well. Those other tests, which might actually help a patient, aren’t getting done because the machines have been purposed to COVID testing.

      Those machines have a limited capacity and costs hundreds of thousands of dollars, and are built when ordered, Adding a new machine at a lab would take at least 6 months and what would you do with it when volume returns to normal?

      Who is going to pay to mothball the machine and maintain it while waiting for the next pandemic?

      Sure, instant testing at low cost would be nice, but unless you can get Dr McCoys Tricorder from Star Trek, it just isn’t practical.

      Testing capacity is a limited resource and should be used wisely, not promiscuously.


      1. Machines cost hundreds of thousands?

        So what? What this pandemic costs that’s peanuts.

        We could buy 2000 machines, forty for each state, for half a billion. Fast track the production for another half billion.

        We’ve already dropped 3 or more TRILLION, with another 1-3 Trillion in the works.

        The countries that have been successful in containing the virus have tested, locked down and contact traced.

        We have done none of those well. Even the lockdown was half assed.

        Hard to get a comprehensive approach when the administration spent more effort fighting with governors, insulting mayors and ignoring the fact that Americans are dying in huge numbers so they can plan rallies. Plus the administration has stated that they are not interested in testing. Too many positives.

        And the president has finally allowed his royal visage to be seen with a mask.

        And people wonder why we are not succeeding.

        Liked by 1 person

        1. Do you think this kind of machine can be popped out like hockey pucks?

          They aren’t mass produced like cars, and the parts or not off the shelf. There just isn’t the capacity to produce them by the thousands.

          Some problems cannot be solved by hitting them with bag of money.

          The US already conducts more tests per capita than any other country, by far, at 160 tests per 100,00o people

          John Hopkins testing date


          1. We built Liberty ships in a month or so. That’s a 450 foot vessel with twin screws, engines, etc.

            This testing is either a priority or it isn’t.

            Liked by 1 person

          2. Again, we test more per capita than any other country by a very wide margin.

            There are a lot more more people who can build ships or learn their part very quickly than can produce and calibrate automated testing equipment, not to mention operate it.

            But again the point is that we are doing more testing for little gain. We have to prioritize those tests that a doctor needs to treat a patient over those that are just data points.


          3. John Hopkins says differently, though I don’t think JH included countries with populations under 100K. I don’t think comparisons with very small, wealthy countries like San Marino with a population under 34K are of any use.

            JH has US testing at 160 per 100K which is ahead of any of the large countries on either list.

            But the point remains that statistical testing that has no use in treatment should not have the same priority as medically useful testing.


          4. Medically useful testing is obviously fine for normal, non-pandemic times.

            But with a deadly contagion like COVID, the importance of containment and prediction is hard to overestimate.

            Again, waiting two weeks, or even one week, is kind of useless except for the assurance value for the patient. And even that is questionable.

            True, many of the countries are small. But we are not that far ahead of many and behind U.K.

            Liked by 1 person

          5. Perhaps JH and your cite count tests differently, but in any case, the US is not suffering from a lack of testing but from exceeding our capacity to process the tests, which is not readily scalable without commandeering university research capacity, which is counterproductive.

            Currently, we are emphasizing testing of minority communities mostly for political reasons. The data might be useful, but it is not time critical.

            Priority should be given to treatment-critical testing instead of demographic research.


          6. Why would it be counterproductive to commandeer university assets? It is a NATIONAL HEALTH EMERGENCY, and all available assets should be put to use to help contain it.

            …”we are emphasizing testing of minority communities mostly for political reasons. ”

            Cynicism at its finest. With minority communities taking the brunt of the infections, there is good reason for testing to be focused in those areas. To say it is “not time critical” is condemning folks to the idea of wondering if they have it and are passing it on.

            As far as unneeded testing, should I ignore a call telling me that someone I have been in contact with has tested positive? Or I forgot to wear my mask into Walmart and realize that I may have been exposed? Being prudent or just fearful?


          7. Because universities use those machines as research tools to find treatments and vaccines, and if the machines are tied up running tests to make minority communities feel like their governor or mayor cares about them, the treatments and vaccines that could save them will be delayed.

            Testing if you have reason to believe you have been exposed is of limited use as you will likely test negative until you have at least some symptoms anyway so you will think you are OK, until you aren’t.


          8. …if the machines are tied up running tests to make minority communities feel like their governor or mayor cares about them”

            So minority communities don’t deserve to be treated like everyone else. Noted.

            …”you will likely test negative until you have at least some symptoms”… Horse Hockey! And you know that statement is patently false. How many tests have come back positive where the patient was asymptomatic? You usually make valid scientific points, but in this case your just flat out wrong.


          9. no. minority communities deserved to be treated EXACTLY like everyone else.

            That means not having pop up testing for asymptomatic people based on the makeup of the neighborhood.

            YOu might be confusing test types.

            Antibody tests will come back positive on asymptomatic carriers 2 weeks after they were infected.

            But the actual tests for the virus have a very high false negative result prior to symptoms.

            The false negative tests run between 67% and 100% in the first 4 days after exposure

            fales negatives prior to aymptoms


          10. “That means not having pop up testing for asymptomatic people based on the makeup of the neighborhood.”

            There was a pop-up test site set up at Larkspur Middle School about two weeks ago. I live in that neighborhood and it is NOT a majority-minority area by any stretch.

            And anti-bodies are showing that immunity is lost a few months later. So much for herd immunity.


          11. That doesn’t mean what you think it means.

            Yes the antibody titer declines over a few months, but the cells that have been “trained” to make those antibodies and recognize the virus remain forever.

            So, while it took you body a week to ten days to ramp up a defense the first time, the next time the titer will jump back up and the T-killer cells multiply to peak levels in only a couple of days, so you probably won’t even know you were exposed the 2nd time.

            The same thing happens with the common cold. You get it over and over, but never as bad as the first time.


  2. Yes. Plus, the tests are crap. They still have no idea of the what the medical types call selectivity and sensitivity of the devices. False positives in both the active virus and antibody tests, combined with the still low probability of a true positive (<< 0.1) means that given a positive result it’s still 50-50 on the result.

    I said early on, surveillance testing was a fool’s errand. It is the cause of the large number “asymptomatic infections”.

    Trust this, when they open schools, all Hell will break loose.

    Of course, Trump is still an idiot.

    Liked by 1 person

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