Clotters, sorry to move into the Microbiology world, but it seems appropriate to quote my respected colleague, Rodney Rohde, PhD on Covid-19 testing.
“My thoughts on laboratory testing since it's on everyone's mind. Please understand, the only true way to know if someone is positive or negative with ANY infection / microbe is to perform a #MedicalLaboratory test. Period. While physicians, nurses, your mom, grandma, and 3rd cousin might tell you "they know they only have an allergy, or a cold, or whatever" they DO NOT know with 100% accuracy. This is what my colleagues and I do—provide the laboratory medicine result one needs to the physician to determine your infection, condition, and build a healthcare plan from it.
We MUST prioritize testing to protect those most vulnerable and to understand where the virus is spreading geographically. What we shouldn't do is panic and run to the ER or the doctor begging for a test if we feel fine. I know, you may want to know you are "negative" but really, what good is it if you are negative and you were feeling fine anyway? You will likely want another test in a few days.
We simply can't continue to overwhelm our laboratory professionals with unnecessary testing. Likewise, even if you are positive and you had mild symptoms, you will be asked to self isolate for a couple of weeks. You can do that without a test. WE DO IT all the time. I bet you don't run to the doctor for every cold, tummy bug, or even flu bug you've had in the past. Right? The human immune system is amazing!
NOW, if you are in the at risk population or you have major health issues such as shortness of breath associated with pneumonia, then YES, you likely need a test. BUT, call ahead to plan. We do NOT need hundreds of people overwhelming testing centers or hospitals. I can't state this enough - WE CAN'T OVERRUN our ER 's and ICU's. If we do, then we are in real danger of losing lives."