This one: https://www.labor-bayer.de/ But get the price confirmed first again, some minerals tested are bloody expensive. Tested it last a year ago, at which time that price remained stable already for 6 years. Usually I test it together with potassium, iron, zinc, copper, lithium - all in whole blood, and all about the same price. Also test stuff with them a bit more expensive (€24,--38,-) but not available through my GP, like CoQ10, retinol and RBP, methylmalonic acid, GSH-Px and SOD1.
I get the blood drawn at a local laboratory in Austria and they send it in. And don't have to pay for the blood-draw itself, since I come with a referal from my GP for homocysteine anyway.
The upper part of the throat where tonsils are, at that height exactly is where the last two vertebrae are placed that are known to cause CCI and only at a coupe of centimeter of distance....
Current medical practice is absurd by cutting the body into parts that are strongly connected, to its possible that infection migt be causing some type of CCI and malfunction in general at that area affecting the whole body, ligaments, etc.. and while solve it with surgery or antibiotics others can solve it by moving the vertebrae to the right position like Jeff or Jen Brea.
It seems all the fuss is in that area of the body, those 5-10 cm and sorroundings. Looking from the front (throat) or the back.
I have hard lumps on my hard palate and the junction between my hard and soft palate - roughly in the tonsil area. When my symptoms get worse, I feel pain in that area. I've been trying to find someone to remove them for years. I think you're onto something.