As far as I know the amount of blood they take for blood work depends on what tests are going to be run. I don’t know how many tests there are out there except I have work done annually and they test for cholesterol, plus a few others related to blood pressure and thyroid conditions (more looking for residual levels of the meds prescribed or indicators of the same…) and they have never taken more than 4 of those smaller tubes.
That is not much, I had on incident when I was much younger getting hit in the face with a snowball and lost a LOT more via the nosebleed.
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