The Cancer-Patient's Guide to Finding Out You Don't Have Covid-19 in Ten Steps, Most of Which are Difficult

The catch is inevitable--this method is the last you'd like to try. But it's effective!
First, have some condition like cancer requiring you to get a CT scan every few months. 
Second, go sip that cocktail of radioactive somethingorother, chalk and water, the stuff that lights up your insides so the CT scan perceives lurking carcinogens, in case they're there. 
Third, reflect on the fact that you've lifted your face shield and mask to drink that stuff, but have done so in an empty waiting room--how it ever emptied out, you'll never know, but wish that someone were Watching Over You in a good way (but if they are, they never talk to you--which is unpleasant). 
Fourth, lie on the scanner --the technician asks you to close your eyes, but you think she says hold your breath, and do so. You can still see. No harm done?
Fifth, see your oncologist, who's sitting less than six feet away, but your mask and shield are back on and you somehow think "she doesn't count," and lean further forward to see your scan.
Sixth, perk up when she says, "your lungs are clear!" And that's the first thing she says, after giving you the thumbs up sign.
Seventh, listen with alarm and interest to the story she tells: some physicians--but not in this hospital!--ordered scans and found, while looking for cancer cells, the characteristic signs of COVID in the lungs. Yes, in asymptomatic persons, persons manifesting no coughs, no fevers, nothing. But your lungs are just fine. 
Eighth, reflect: unless you've contracted the illness while sipping your CT cocktail and the bug just hasn't shown up yet.
Ninth, head home happy you're COVID free and also, for the moment, cancer free.
Tenth, Schedule a Zoom virtual cocktail hour with your pals. As you lift a goblet of red wine to your lips, consider how much better it tastes than those two liters of Chalk De Luxe you drank for the CT scan.