Doesn't spinal fluid contain stem cells? Think there are 4 main bodily fluids that contain stem cells. Blood - we donate much more than they use in emergencies. Placenta - well, they take that away and 'dispose' of it. Urine is another. I remember hearing that the owner of a 'Portaloo' company was also the owner of a pharmaceutical company. There is a lot of Urea/Uric acid in pharmaceuticals and beauty products....

I am sure the spinal fluid is used for some weird shit. I am convinced of it. It’s a very invasive procedure that is probably not necessary

Idk, yrs ago Nana had Pseudotumor cerebri, a brain condition, and they had to pull spinal fluid out periodically because I was making too much of it and to test it.
Their tests revealed the diagnosis but not the cause. No one knows the cause.
That is a good question tho.
What do they get out of testing spinal fluid they can't get from their normal blood tests?

And what do they do with it? Do they take more than they need and utilize it in some other way?
It seems a pretty sacred fluid.