I would like to see a test that tells us if we already HAD COVID-19. What if we found out that 90% of the population has already had it and didn't know (not likely, I understand, but we have no idea). My friend was self quarantined, a few weeks ago because she had been exposed to someone who test positive for COVID -19. Out of the four people present at that gathering, 2 tested positive, 2 did not. Of the two who tested positive, one barely got the sniffles. The other it was like a standard cold, no chest issues or flu like symptoms. Her husband, on the other hand, is now in the hospital (he is 10 years older than she is).
If the husband hadn't ended up in the hospital, none of those 4 women would have been tested. No one thinks twice about a cold or the sniffles. This would have looked like a 20 % infection rate, when it was really a 60% infection rate. And if the husband hadn't ended up in the hospital? It would have looked like a 0% infection rate. If only he had been tested, and IF he died (he has not), it would have been 1 tested, 1 died, not 3 had COVID 19 and 1 died. 33% (in this simulated death example) case vs 100% mortality rate. That's a big difference to throw into the statistics.
Right now, all anyone can say is that out of the X people who were tested, Y many died or were seriously ill. We cannot actually say that out of X people who actually HAD COVID-19, Y many died. I'd like to know what the herd immunity REALLY is. That would calm some of the panic, IMO.
ETA: What if the two who tested negative had actually previously HAD COVID-19? That changes the stats even more.