Sunday, June 14, 2020
False Positives with Covid-19 Tests
False Positives with Covid-19 Tests
A story by Richard Harris on NPR, June 14, 2020 -- titled, “What Mussels Can Teach Us About False Positive COVID-19 Tests.”
The stories I have been collecting relating to scientific discoveries and dyslexic talents can sometimes appear in major news stories in unexpected ways.
In recent months stories on Covid-19 have dealt with the importance in the disease of Acute Respiratory Distress Syndrome (ARDS). At a dyslexia conference in Denver years ago, I met a physician who introduced me to the dyslexic doctor who was the first to identify ARDS and he set up an interview. It turned out that the first paper on ARDS by the dyslexic doctor (Thomas Petty, MD) was rejected by three major US medical journals, but was accepted and featured by the UK medical journal, The Lancet.
The Lancet article was read by US doctors in Viet Nam, who saw the great importance of recognizing and understanding proper treatment of ARDS. They said, “This is what is killing our troops.” (A sidelight of this story is that one cannot always trust a “peer review.” Sometimes the current “expert” in the relevant field hates the new idea or misunderstands the new discovery -- and repeatedly tells the major US journals not to publish the paper.)
A somewhat similar story appeared today in an NPR report by Richard Harris concerning false positives for Covid-19 with tests that involve PCR. This is a story that shows how a great advantage can turn out, under certain conditions, to be a great disadvantage.
The Polymerase Chain Reaction (PCR) was discovered by Kary B. Mullis, who received a Nobel Prize in 1993 for the discovery. According to the Nobel Prize presentation at the Royal Swedish Academy of sciences: “Using this method it is possible to amplify and isolate in a test tube a specific DNA segment within a background of a complex gene pool. In this repetitive process the number of copies of the specific DNA segment doubles during each cycle. In a few hours it is possible to achieve more than 20 cycles, which produces over a million copies.”
Mullis made the discovery, but he was not the first. The PCR process was in fact observed much earlier in a laboratory accident years before. The researcher and her laboratory associates are still embarrassed that they did not realize what was unfolding in their lab at the time. They were trying to destroy DNA -- but, instead, with each try they were creating more DNA. This happened several times. The associates tried to help the main researcher. But the experiment repeatedly failed -- so they gave up and walked away from it.
This story was told to me by a friend who was a cancer researcher at the University of Colorado. I provided a longer version of this story in my book Seeing What Others Cannot See (Prometheus Books, 2017, pp. 69-71). My comment: “Of course this story is so upsetting [to the researcher] because she had the discovery right there in front of her, but she was so focused on her seemingly failed project that she could not see the value of her experiment’s results. Such stories teach us. Sometimes a gift is seen only as a problem, something that would be quickly wished away had we the power. Sometimes the most important thing is to be able to recognize the gift for what it is, even though it was not requested or desired. For this to be possible, it is helpful (in spite of one’s training) not to be wholly focused on the narrow interests of the moment -- no matter how serious the task, no matter how large the grant, no matter how urgent the deadline. One has to be open to new possibilities, to looking at things in a different way, to being able to see what you have been given, even when it is not what you asked for.”
In the story by Richard Harris, a scientist who is a specialist on marine organisms had noticed false positives with tests using PCR when he was looking in certain waters for evidence of a specific type of mussel shellfish. The CPR tests had picked up a tiny contaminant that had been increased many times by the CPR, forming a false positive. The test said the shellfish was there, but the scientist knew this was not possible. Harris quotes an expert who said that tests for Covid-19 that employ PCR as part of the test might, in similar fashion, sometimes pick up a tiny contaminant and increase it many times to create a false positive for Covid-19 in human beings -- of course, thereby, creating many obvious problems. -- TGW