Velandy Manohar, MD
Distinguished Life Fellow, Am. Psychiatric Assoc.[APA]
Medical Director, Aware Recovery Care-CT. [ARC], President, ARC In-Home Addiction Treatment, PC
Member- CT. State Medical Society Committees – 1. Bioethics, 2. Quality of Care,3. Disaster Preparedness.
Member- Governance Committee of Consumer Advisory Council of Office of Health Strategy-CT
Founding member- Psychotherapy Caucus of APA [Past Steering Comm member]
Founding member- Community Resilience Collaborative- Mx County-CT [Effects of Childhood Trauma.]
Member- 1. Advisory and Review Board- Whiting Forensic Board- DMHAS-CT,2. Medical Advisory Board- Commissioner of Motor Vehicles- [DMV -CT] 3. Hearing Panel- CT. Medical Examining Board-[DPH]
CT. Multi-Cultural Health Partnership- Nancy Berger Member Award- 2012.
American Health Council- Best in Medicine- 2018
IHAT Addiction Institute- First Impact Award Recipient- 2019
Major Confounding issues clouding Testing kits, procedures.
I.
www.coronavirus.gov and https://www.cdc.gov/coronavirus/.
https://drsircus.com/general/untrustworthy-coronavirus-tests-and-statistics/
Untrustworthy Coronavirus Tests and Statistics
Published on March 2, 2020
What we are being told everyday about the virus and its victims would not hold up in a court of law. Medical authorities though are having a field day coming up with the best arguments for throwing everything at the coronavirus, even if it means closing the world down, keeping everyone in their houses, crashing the economy; pretty much stopping as much human activity as possible. The world is panicking as 60 countries report coronavirus infections and as I write, the stock market is set to crash again.
Yet all of this is based on the testing for coronavirus, which is touch and go all the way. Stories in several countries suggest people are having up to six negative results before finally being diagnosed. Meanwhile, officials in the epicenter of the epidemic, Hubei province, China, “have started counting people with symptoms rather than using the tests for final confirmation,” according to the BBC. Meaning we do not know if the deaths are due to other causes like regular forms of pneumonia and flu.
Hard to tell yet if the medical response is more of a threat than the virus itself,[Especially because of the unreliable tests and the risk posed by used of unauthorized or unapproved medications. VM] which is reported to be quite mild for at least 80 percent of the population and especially mild for children. It is impossible to keep up with the fast-changing coronavirus statistics: the number of confirmed cases in new countries seems to roll like ticker tape and yet there is no accountability for the quality of the information.
World governments are obligated to follow world medical institutions responses to the coronavirus pandemic. They have no choice and neither do we if we are ordered to close our lives in quarantine. The doctors and their parent medical organizations get to play God, tough luck if you do not like it. In a pandemic medical truth becomes divine truth even if there is little truth in the narrative. [This is especially pernicious and dangerous because the CDC and other organs of the Govt have provided us with flawed unworkable tests and untrustworthy data about the incidence and prevalence of COVID -19 infections. VM]
The Quicksand of Coronavirus Tests
A study in the journal Radiology showed five out of 167 patients tested negative for the disease despite lung scans showing they were ill. They then tested positive for the virus later. Doctors like to assume patients like these have the coronavirus forgetting to mention that lung scans show up the same for regular pneumonia patients, as well as from the flu and fungus infections in the lungs, all of which will show up on lung scans.
Thus, the question is being raised that the RT-PCR test for the new coronavirus is based on flawed science. False negatives in diagnostic testing lead to the release of infected people, motivate extreme containment measures that have been implemented. False negatives can explain why official figures are too low. Or that patients with other diseases are not being diagnosed with coronavirus but eventually after enough tests doctors finally get what they are looking for or what are called false positives.
Dr. Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases, said that when various state laboratories performed quality control tests on the kits, the labs “identified some inconclusive results.” “Specifically, some public health labs at states were getting inconclusive results and what that means is that test results were not coming back as false positive or false negatives, but they were being read as inconclusive,” said Messonnier.
The CDC designed a flawed test for COVID-19, then took weeks to figure out a fix so state and local labs could use it. New York still doesn’t trust the test’s accuracy, and neither should we. ‘Confusion breeds distrust,’ which is growing each time China changes how it counts coronavirus cases. China’s lost a lot of credibility and faith in the accuracy of its data with its swift and frequent changes, international researchers say.
What are the consequences of inconclusive test results?
A false positive could theoretically expose someone without coronavirus to a hospital setting where they run the risk of being exposed to other types of illnesses, or far worse, a quarantine setting with other patients who have tested positive for coronavirus, where (given how contagious it is) they would most certainly catch it, or even worse the prospect of being harmed by unapproved and unproven drugs administered by panicked Doctors, medical staff and health officials and administrators who have differing motivations to create data that suits their purposes.VM]
A false negative means that someone with COVID-19 is theoretically released back into the world to expose otherwise healthy people to the virus, putting entire swaths of the world on edge. “Testing for coronavirus is not available yet in New York City,” city Department of Health spokeswoman Stephanie Buhle said at the very end of February. “The kits that were sent to us have demonstrated performance issues and cannot be relied upon to provide an accurate result.”
Conclusion
Currently, most pandemic-prone diseases, including coronavirus, are diagnosed by polymerase chain reaction (PCR), a molecular technique that often requires special laboratory machines and highly trained technicians to operate them. PCR tests are difficult to scale or decentralize. Bill Gates points out that portable versions of these molecular diagnostic machines need to be distributed throughout Africa to prevent the spread of coronavirus. We do not read about anyone gearing up to provide such equipment.
Running the test machines also requires a consumable test kit, and the number of coronavirus cases in China has exceeded its laboratory testing capacity due to a shortage of PCR testing kits. Consequently, China has had to resort to using CT scans as a hospital-based rapid test to screen infected patients for coronavirus, followed up by laboratory-based testing for confirmation. Many clinics do not have the expensive machines to do CT scans and good thing because these scans do not test for the virus. They can only report on the state of the lungs but not what is causing any infection.
In our age of evidence-based medicine, nothing is more important than the quality of laboratory tests. It is commonly thought that laboratory tests provide two-thirds to three-fourths of the information used for making medical decisions. If so, test results had better tell the truth about what is happening with our patients.
A study five years ago estimates that in the United States, some 251,000 deaths per year occur because of errors in medical care. This makes medical errors the third leading cause of death, only after heart disease and cancer. Lab test failures contribute to delayed or wrong diagnoses and unnecessary costs and care. For context, a 2014 study estimated that diagnostic errors happen about 12 million times per year in U.S. outpatients.
II
https://futurism.com/neoscope/coronavirus-covid19-test-kits-broken-america-scarce-china
CORONAVIRUS (COVID-19) TEST KITS ARE BROKEN IN AMERICA, SCARCE IN CHINA
INACCURATE OR ABSENT RESULTS PUT A MASSIVE, INCREDIBLY DANGEROUS PROBLEM.
BY FOSTER KAMER / FEBRUARY 13, 2020
THE BIG CATCH in containing the COVID-19 coronavirus epidemic has been, of course, detecting it. Testing needed to be developed, and then those tests need to get all over the world. The problem, currently: In America, the rush to get testing kits out in America hasn’t gone well, with faulty kits being shipped around the country. And in China, there simply aren’t enough kits to go around.
On a Wednesday afternoon press call, the Centers for Disease Control and Prevention (CDC) gave journalists the lowdown: Some of the kits ended up being shipped with faults and issues that deliver inconclusive results. That doesn’t mean they were producing false positives or false negatives, but that they just weren’t producing the results the CDC needed them to produce — a non-result.
That said, the tests need not just be conclusive, with an answer, but a correct answer
– A false positive could theoretically expose someone without coronavirus to a hospital setting where they run the risk of being exposed to other types of illnesses, or far worse, a quarantine setting with other patients who have tested positive for coronavirus, where (given how contagious it is) they would most certainly catch it. [Even worse for unsuspecting persons who test positive- the prospect of being harmed by unapproved and unproven drugs administered by panicked Doctors, to persons misdiagnosed because of faulty tests medical staff and health officials and administrators who have differing motivations to create data that suits their purposes.VM]
– A false negative means that someone with COVID-19 is theoretically released back into the world to expose otherwise healthy people to the virus, putting entire swaths of the world on edge (with the presumption that, of course, they’re healthy). These undiagnosed individuals can either recover slowly from an illness other than COVID 19 or get better from milder case of COVID -19 or get worse abruptly and die of sever illnesses like Pneumonia or Liver failure. Some of the factors may include use of unproven and unauthorized medications-VM
When the state receives these test kits, their procedure is to do quality control themselves in their own laboratories. Again, that is part of the normal procedures, but in doing it, some of the states identified some inconclusive laboratory results. […]
When a state gets the test kits, they must verify that it works the same in their lab that it worked at CDC. […] Some public health labs at states were getting inconclusive results and what that means is that test results were not coming back as false positive or false negatives, but they were being read as inconclusive.
So now, the CDC is re-manufacturing the reagents (or liquids used to produce results in testing settings) and re-shipping the tests, trying to get them out as quickly as possible. Meanwhile, in China, there just aren’t enough testing kits to go around. Per the New York Times:
A major bottleneck has been a shortage of nucleic acid testing kits used to confirm the presence of the coronavirus. So, Dr. Zhang proposed that doctors could first use CT scans to detect pneumonia and quickly isolate and treat patients who have it. CT scans are convenient and can produce immediate results, Dr. Zhang said. Experts say people infected with the coronavirus would be likely to have lesions in both lungs. [We can see Pneumonia type of shadows on the periphery of the Lungs in the quickie Chest CT, but we will not know the cause therefore we will not be able to allocate the resources appropriately to do contact tracing and enforce quarantining of the contacts.VM]
Throughout all of this, one thing’s perfectly clear: There is nothing if not a sense of urgency in the race to get these tests shipped, stocked, and producing accurate results. The race is on
II
https://futurism.com/neoscope/coronavirus-covid19-test-kits-broken-america-scarce-china
CORONAVIRUS (COVID-19) TEST KITS ARE BROKEN IN AMERICA, SCARCE IN CHINA
INACCURATE OR ABSENT RESULTS PUT A MASSIVE, INCREDIBLY DANGEROUS PROBLEM.
BY FOSTER KAMER / FEBRUARY 13, 2020
Right. So. Bad. By the numbers, the current CDC testing kit situation goes like this:
– 200 kits total were shipped across all fifty states.
– 200 more kits were spread out across 30 countries.
– 700 to 800 samples come out of each kit.
That’s, at a rough estimate, 15,000 tests. The CDC didn’t indicate how many of the tests were faulty. Per Dr. Nancy Messonnier, the Director of CDC’s National Center for Immunization and Respiratory Diseases, from yesterday’s phone call:
When the state receives these test kits, their procedure is to do quality control themselves in their own laboratories. Again, that is part of the normal procedures, but in doing it, some of the states identified some inconclusive laboratory results. […]
When a state gets the test kits, they must verify that it works the same in their lab that it worked at CDC. […] Some public health labs at states were getting inconclusive results and what that means is that test results were not coming back as false positive or false negatives, but they were being read as inconclusive.
So now, the CDC is re-manufacturing the reagents (or liquids used to produce results in testing settings) and re-shipping the tests, trying to get them out as quickly as possible. Meanwhile, in China, there just aren’t enough testing kits to go around. Per the New York Times:
A major bottleneck has been a shortage of nucleic acid testing kits used to confirm the presence of the coronavirus. So, Dr. Zhang proposed that doctors could first use CT scans to detect pneumonia and quickly isolate and treat patients who have it. CT scans are convenient and can produce immediate results, Dr. Zhang said. Experts say people infected with the coronavirus would be likely to have lesions in both lungs. [We can see Pneumonia type of shadows on the periphery of the Lungs in the quickie Chest CT, but we will not know the cause therefore we will not be able to allocate the resources appropriately to do contact tracing and enforce quarantining of the contacts.VM]
Throughout all of this, one thing’s perfectly clear: There is nothing if not a sense of urgency in the race to get these tests shipped, stocked, and producing accurate results. The race is on.
III.
https://www.sciencenews.org/article/coronavirus-testing-diagnostic-covid19-united-states
What you need to know about coronavirus testing in the U.S.
Testing remains limited in the country
By Tina Hesman Saey
MARCH 6, 2020 AT 6:24 PM
U.S. government officials say a million promised tests for diagnosing coronavirus infections will soon be in the mail. But that still leaves many state and local laboratories without the ability to test for the virus, crucial for curbing its spread around the country.
Some states have developed their own tests. Clinical testing companies are now joining the ranks. LabCorp announced March 5 that physicians or other authorized health care providers could already order its test. Quest Diagnostics announced the same day that the company will also offer commercial tests as soon as March 9, pending U.S. Food and Drug Administration reviews. Participation of those two commercial laboratories could greatly expand testing capacity in the United States.
But for now, “we still find ourselves as a country with pretty limited capacity to test,” says Michael Mina, an epidemiologist at the Harvard T.H. Chan School of Public Health in Boston.
Here’s what you need to know about coronavirus testing in the country.
What’s the status of testing?
As of March 11, 81 state and local public health laboratories in 50 states and Washington, D.C., have successfully verified COVID-19 diagnostic tests and are offering testing, according to the U.S. Centers for Disease Control and Prevention. But even states that have tests may have only a single kit, containing enough material to test just 700 people, Mina says.
As of March 13, roughly 14,200 tests have been conducted nationally, according to an analysis from the Atlantic.
That’s up from the 1,583 people that had been tested at CDC, as of March 5. Contrast that with the United Kingdom, where 20,388 people had been tested as of March 6. At that point, only 163 cases of COVID-19 had been detected there.
As of March 13, U.S. health officials have reported over 1,885 coronavirus cases across 47 states and Washington D.C., including 41 deaths. More cases can be expected as testing ramps up, experts say.
As more cases are found, health officials will need to test contacts of people who carry the virus, and other ill people in affected communities may demand tests, all escalating the need for more tests.
Vice President Mike Pence told reporters March 5, “We don’t have enough tests today to meet what we anticipate will be the demand going forward,” according to CNN. But having companies’ tests in the mix could help testing ramp up.
To get a more complete picture of how widespread the virus is in the United States, “we’re going to need millions and millions and millions of tests,” said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in Bethesda, MD., during a CNN town hall on March 5.
Why can’t the virus be tested for like influenza?
Many doctors’ offices can do a rapid influenza test. But those flu tests don’t use PCR, Satterfield says. Instead, they detect proteins on the surface of the influenza virus. While the test is quick and cheap, it’s also not nearly as sensitive as PCR in picking up infections, especially early on before the virus has a chance to replicate, he says. By the CDC’s estimates, rapid influenza tests may miss 50 percent to 70 percent of cases that PCR can detect. The low sensitivity can lead to many false negative test results.
Flu tests also aren’t as specific for a particular virus strain as PCR is. About 5 percent to 10 percent of the time, flu tests may mistake a different virus for the flu, creating a false positive result. “Specificity is a big deal when you’re testing large numbers of people who aren’t expected to be positive,” Satterfield says. “If you’re going to test in one of the states that doesn’t have a coronavirus outbreak right now, with a specificity of 90 percent, 10 out of every 100 people are going to show up positive even though the coronavirus isn’t there yet.”
“Accurate diagnosis is a very high imperative for this [coronavirus],” Satterfield says.
An additional benefit of a PCR test is that it may be able to detect viruses earlier in an infection than a flu-style test can, he says, perhaps not in the first day, but a couple of days into an infection when the virus is replicating strongly, but the body’s immune system hasn’t yet begun to fight and produce symptoms.
“In every infectious disease I know of, that is the most contagious period for a person; the point in time when the virus has multiplied to its maximum capacity and the body has not yet started to rein in on it,” Satterfield says. Being able to identify people in that period and isolate them from others could help curb the spread of the disease.
https://towardsdatascience.com/statistics-and-unreliable-tests-coronavirus-is-difficult-to-contain-e113b5c0967c
THE 2020 NOVEL CORONAVIRUS OUTBREAK | THOUGHTS ON PROBABILITY AND STATISTICS
Bayes’ Rule, Unreliable Diagnostic Testing, And Containing COVID-19
How false negatives in diagnostic testing lead to the release of infected people, motivate extreme containment measures have been implemented, explain why official figures are too low.
The COVID-19 outbreak explained with Bayes’ Rule.
Andy Chen, Feb 19,2020
Wuhan coronavirus. Novel coronavirus. COVID-19.
We are currently in February 2020. Over the past month, a deadly virus has been spreading throughout China and the world, sending the infected to the ICU and trapping others in their homes. As authorities try to manage this crisis, they face the challenging issue of containment — sending the infected to quarantine, while allowing the non-infected to go free.
Here is the scenario. You have a cough and a fever. There is a chance that you have caught COVID-19 — the virus spreading throughout the world. You don’t know what this chance is, and you don’t want to take chances, so you seek advice from your doctor.
The issue from the authority’s perspective is different. You want treatment, but the authorities need to contain the spread of the virus. From their point of view, there are 4 main outcomes of your visit to the doctor.
1. If you are infected and diagnosed with coronavirus, they will quarantine you for the public benefit.
2. If you are not infected but you are diagnosed with coronavirus,[False Positive] they will wrongly quarantine you, causing you inconvenience. The public will suffer no major harm, but the authorities will have to expend a small amount of resources.[ To try to track down contacts and test them]
3. If you are infected and not diagnosed with coronavirus, [False Negative] they will wrongly release you, causing you to spread the virus. This puts the public in grave danger of an outbreak.
4. If you are not infected and not diagnosed with coronavirus, they will rightly release you and save some resources.
The two mistakes that the authorities can make is scenario 2 and 3. Scenario 2 is a minor inconvenience (if not done too often), but scenario 3 is the major issue which can cascade into a larger outbreak, even if only done once. If an outbreak occurs, they will have to do contact tracing for possibly hundreds of people, given the contagiousness and lethality of coronavirus. This will be extremely costly for them, so their primary interest is in minimizing the probability of the third scenario.
Thus, the authorities need to make an accurate diagnosis, so that they can avoid releasing the infected and quarantining the non-infected. To achieve this, the authorities first make an initial assessment of all suspected infections, whether they are patients at the medical clinic, or travelers from places with active outbreaks.
Thus, the authorities need to make an accurate diagnosis, so that they can avoid releasing the infected and quarantining the non-infected. To achieve this, the authorities first make an initial assessment of all suspected infections, whether they are patients at the medical clinic, or travelers from places with active outbreaks.
The Probability and Statistics Behind Diagnostic Testing
After gathering enough clues, a doctor may suspect coronavirus. To confirm this suspicion, the doctor will order a diagnostic test.
Misconceptions about what the diagnostic test result means
A diagnostic test is performed by collecting samples from your body (e.g. mucus in the back of the nose) and looking for presence of the virus in those samples. It seems simple enough, and people have a lot of faith in science. This may lead people into making this first mistake.
Incorrect interpretation: a positive result means a patient has novel coronavirus, while a negative result means that a patient does not.[ It is not all the Straight forward.VM]
This is not true, because the test is not always reliable. There are many reasons why a test may give a misleading result:
• A patient in the very early stages of an infection may not excrete a detectable amount of virus.
• The virus itself may only exist deeper inside the body, hence being inaccessible by a swab test.
• There may have been accidental contamination of the sample. [Including the possibility of cross contamination and even mislabeling at various points along the pat taken by the sample from the time it is collected, and the results are reported. VM]
In general, the people who make the testing kits will specify the reliability of the test.
Suppose that a company now markets their test as “90% accurate”. This can lead to another common mistake.
Incorrect interpretation: for a 90% accurate test, a positive result means 90% chance of being infected, and a negative result means 90% chance of not being infected.
This interpretation is also not true, but is actually surprisingly common in the medical community— the great psychologist Gerd Gigerenzer shows how doctors misinterpret the results of mammogram results article.
Bayesian probability explains what the diagnostic test really means
The correct way to evaluate a diagnostic test requires thinking in terms of Bayesian probability. To put it simply, Bayesian probability involves having a prior probability and then using new information to update it. In terms of diagnostic testing, the prior probability is the doctor’s belief about whether the patient is infected or not. The test result is used as information, and this changes the doctor’s belief.
We can formulate the reliability question in terms of math equations.
PLEASE READ THE ORIGINAL PAPER. PLEASE REVIEW THE MATHEMATICAL RELATIONSHIPS BETWEEN SPECIFIC COMPONENTS;
We now have two new unknown probabilities.
1. The probability of a positive result given that a patient is infected. This number should be high — infected patients should be getting positive test results.
2. The probability of a positive result given that a patient is not infected . This number should be low — non-infected patients should be getting negative test results.
These two probabilities are actually measuring of a test’s reliability, and they can be expressed in terms of two quantities: sensitivity and specificity.
Sensitivity
• Probability of a positive result given infection.
• The test is “sensitive” to the presence of coronavirus. If the coronavirus is present, the test will detect it.
• Ideally, close to 100%.
Specificity
• Probability of a negative result given no infection.
• The test is “specific” to coronavirus. If there is no coronavirus infection, the test will not detect anything, and returns negative.
• Ideally, close to 100%.
I should remind you here that I can express probabilities in terms of complements. Infection and no infection are mutually exclusive. Similarly, a positive and a negative result are also mutually exclusive. This means that our calculations will use these two equations, where A and B are events such as “the patient is infected”, or “the test result is positive”.
Given that B has occurred, the probability of A not occurring is still one minus the probability of A occurring.
The probability of infection given a test result
We now have all the tools we need to interpret a test result
• Prior probability — initial belief
• Posterior probability — final belief
• Bayes’ rule — connects initial and final belief
• Sensitivity and specificity — allows us to do computations using Bayes’ rule
Combining these, we get; Couple of mathematical equations;
We now know how to incorporate the information from a test result to change an initial belief into a final belief. Next, we look at diagnostic tests with different levels of reliability and see how their results might affect the beliefs of doctors.
The Application of Diagnostic Tests in Medicine
You followed the doctor’s advice and got a diagnostic test. The doctor now receives a positive or negative result for coronavirus and now needs to make a decision:
1. Prescribe any necessary medication and let you go.
2. Order you to be quarantined [or not. VM]
Decision Making in Medicine — Reducing Uncertainty And Taking Acceptable Risks
To decide when to treat, the doctor needs to have confidence in a diagnosis.
In general, medical practice, a doctor can make two mistakes:
1. You are not infected, but the doctor decides that you are, and gives treatment.
2. You are infected, but the doctor decides that you aren’t, and does not give you the proper treatment / lets you go.
In order to avoid these mistakes, the doctor orders a test. They had a prior belief, and the test is used as information to reduce uncertainty. Once the doctor has enough certainty, the doctor can make a recommendation.
How much uncertainty can be reduced by a test?
We first look at a reliable test. Consider a test that has sensitivity and specificity at 98%. We show what the prior and posterior probabilities of infection are, given a positive or negative result.
• If you think the probability of someone being infected is 80%, then a positive result takes it to near 100% (near certain infection), while a negative result reduces the probability to under 10% (unlikely infection).
• Similarly, if you think that the probability of someone being infected is only 20%, then a positive result increases it to over 90% (likely infection), while a negative result takes it to near 0% (infection is nearly impossible).
• Any initial probability which is greater than 10% increases to a higher probability (>80%) after a positive result.
• Any initial probability which is less than 90% decreases to a lower probability(<20%) after a negative result.
• Since the test is able to change a large range of initial probabilities into final probabilities near 0% and 100%, it resolves the uncertainty of whether a patient is infected or not. Hence it is a reliable diagnostic tool.
THE IDEAL TEST WILL HAVE A 99.9% SPECIFICITY AND SENSITIVITY
• The orange curve (bottom, for negative result) is very close to the x-axis, which would mean that a negative result virtually guarantees a zero probability of infection.
• The blue curve (top, for positive result) is straight up the y-axis and right, which would mean that a positive result virtually guarantees a certain probability of infection.
Diagnostic tests are not perfect — bad luck exists, medical decisions are always risky propositions, fraught with decisional challenges
If the doctor has a reliable test, then a prior belief of 50% can be reduced to less than 5%, or some other very low figure. Unfortunately, these tests are not perfect. There is still a non-zero probability of actually being infected, so the doctor can make a mistake out of sheer bad luck.[i.e. False negative]
How much risk is tolerable?
[This is key.VM]
Because the doctor ultimately has to make a decision, even under uncertainty, the doctor has to decide what is an acceptable risk.
When risk is unacceptable:
• Near-certainty is required before starting a harsh treatment with irreversible side effects.
• A very low probability of having a lethal infectious disease is required before the patient is released.
Where risk is more acceptable:
• Less certainty is needed if the condition is mild and not life-threatening, and the treatment does not have permanent effects.
• Less certainty is needed if the patient is in immediate mortal danger and requires medical intervention as soon as possible (the potential harm of treatment is less than the harm of no treatment).
Decision Making Without Reliable Diagnostic Tests
(From here, we switch focus from general medicine, back to the coronavirus outbreak.)
We’ve established that a doctor needs to resolve uncertainty using a diagnostic test before they can have the confidence to take an acceptable risk.
However, what happens if the diagnostic test is not reliable?
We try to use realistic values. Many flu tests have a specificity of around 90–95%. Keeping in line with this, I assume a 90% specificity (feel free to correct me if you have better information).
I assume a 40% sensitivity. This turns out to be close to the reported sensitivity for COVID-19 corona virus tests. VM
Velandy Manohar, MD