As someone who bids on government contracts for a living, I can see through this opaque maze like it was made of glass. What a shitshow. Example from my biz: Our product is primarily web-based, and lives in the cloud. At first, that was in our own managed data center. But recently we have moved to the Google Cloud Platform. People are naturally security-conscious, so they ask of we are "SOC2 Certified", which is a security standard that covers key physical and electronic security best-practices. (Like required password strength, and servers are in locked cages with restricted access.) Google is SOC2 certified. But for BOTH of us to get SOC2 certification, Google and my company would have to launch a joint effort for about 6 months, to go through every detail of our installations and everywhere our systems touch, write up all the documentation, submit it, and receive our certification in 2-3 months. So around 9 months of work, if everything goes well. And we would have to re-do that exercise every year, or every time either one of us upgraded or changed any of the systems that had been examined. So we say, "our software runs in SOC2-certified data centers" when people ask if we are "SOC2 certified". Because they have no idea what they are asking for; they just googled "good security standard" and came up with the buzzword "SOC2". So I can TOTALLY see how an "EUA approved lab" is something that is absolutely necessary to have and at the same time, unclearly defined. A low-level functionary was protecting their hide one day and wrote an extra line of text somewhere, and now it's policy.
I'm 100% sure that getting EUA certification has everything to do with having the proper documentation in place and proving to FDA that you do. FDA is a good organization, and I know they're doing their best under very difficult circumstances right now. If they start letting everyone do Covid tests without documentation, they're opening everyone up to lawsuits when John Doe tests negative and he goes out and infects Jane Smith's grandma who then dies. I'm also 100% sure getting EUA cert doesn't mean that your test is necessarily that good, but rather that you have a good handle on its sensitivity and specificity. For what it's worth, if your test isn't CLIA certified, you can't get reimbursed for it, so it's a big deal to hospitals too.
I am so so grateful for everything the FDA is doing these days. It just makes my life harder that I can't accept any test that comes across my desk. But I know those poor bastards are working an insane amount to verify as many tests as they possibly can to alleviate the stresses on the current approved tests.