I almost didn't listen to the podcast as I thought the same about it being blood-type. When I checked his website after, he has lists of the various blood tests he uses to evaluate overall health, look for problems. Handy to have whichever doctor anyone uses.
Sorry to hear about your hospitalization. You were lucky to have your PCP there, so many practices have gone to using "hospitalists". I'm using my gyno as my PCP, Dr. Westman for weight and metabolism, and would have to go to an urgent care/hospital for something serious.
Hope you feel better and find the care you need.