Let’s make COVID testing actionable…

We might be testing the wrong people.
An earlier version was posted on March 22 

COVID-19 testing has been getting a lot of attention recently since availability of test kits has been late and slow.


  • TV pundit-doctors complain that they can’t get tests done on their patients.
  • Some people are anxious to know if they have been infected.
  • Scientists are dismayed that they don’t have enough data to accurately calibrate the problem.

The current answer: Prioritize diagnostic testing to sick people who have COVID symptoms (and want to be tested)… 

My question: Is that the right answer?

I think not…


Let’s start with a taxonomy: a simple classification scheme.

My take: we can sort people by 2 main factors:

  • Symptomology: Are they “presenting” any COVID symptoms (“symptomatic”) or not (“asymptomatic”)? Think: very high fever, cough, breathing difficulty.
  • Vulnerability: How likely are they to suffer serious (possibly fatal) effects if they get COVID-infected? Think: old, chronically ill with heart or respiratory issues, compromised immune system.

Now, let’s lay that taxonomy into the MBA tool-of-choice: a 2 by 2, 4-square matrix:

Thanks to former student MC for nudging
me to practice what I used to preach…


OK, that gives us 4 groups to consider.

Quiz time: (1) Into which box do you slot yourself?  (2) How would you prioritize the 4 groups for COVID testing?

The current program is aimed at the right hand column (B & D) — people who are symptomatic.  More specifically, sick people who have severe symptoms.

Frankly, that doesn’t make any sense to me.

I finally heard an interviewer ask one whining pundit-doctor the question: If patients are presenting with COVID symptoms, would you treat them differently whether they tested positive or negative?

The answer: “NO”.

Why waste a scarce test kit if you’re not going to change the course of action?

Patients suspected of having COVID-19 should be presumed to be infected and receive care accordingly.



What about the symptomatic people who voluntarily get a drive-through type test?

A negative test result may reduce some of their anxiety … but it may also be wrong and give them a false sense of security (it’s called a type 2 statistical error — a false negative) … so,  they may keep circulating  … and, any way,  the negative result was for a specific point in time … they may be COVID positive tomorrow or the next day.

Said differently, in my opinion, all of the people who are symptomatic should self-quarantine. PERIOD. No test required.

Consider COVID to be GUPI (Guilty Until Proven Innocent) if you’re symptomatic!


OK, so back to the question: who to test?

My view: test the people in the left hand column … those who are asymptomatic.

Consider Box A first … say, somebody in an eldercare facility who is not exhibiting the symptoms.

I’d test them pronto for 2 reasons: If they test positive, (1) you’d want to get them away from the other facility residents (2) you’d want them to be closely monitored and treated before the do exhibit symptoms and devolve to, say, needing a scarce respirator.

I’d apply that same rule to all frontline healthcare providers, first-responders, and critical service providers (think: grocery store workers)

Keep in mind that these people will need to be tested at regular intervals, not one-and-done since somebody may be virus-free today and infected tomorrow.


What about Box C?

At 1st gush they seem like the innocents … least in need of a test.

Not necessarily.

They may be “hidden carriers” of the virus who stay in circulation and infect people around them. They may be “super-spreaders” who have close contact with multiple groups in different locations.

Take a relatively common case: somebody who has contact with a non-institutionalized vulnerable.  Think: a grandma living with her kids and grandkids.

Grandma is, by definition, vulnerable and should probably be self-quarantining.

But, what good is her quarantine if the folks around her are infected — knowingly or not.

My take: the family, friends and caretakers of vulnerables living at home should be a high testing priority … not far behind the symptomatics in the testing line.


That’s my take … about 180 degrees different than the announced priorities.

Do lots of diagnostic testing … but test the right people.

What do you think?

Follow on Twitter @KenHoma

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2 Responses to “Let’s make COVID testing actionable…”

  1. If test kits are scarce, let’s test the right people! | The Homa Files Says:

    […] Let’s make COVID testing actionable for our  decision matrix and […]

  2. “Science” takes another u-turn… | The Homa Files Says:

    […] ============== For more detail, see our prior posts:  If test kits are scarce, let’s test the right people! and Let’s make COVID testing actionable […]

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