vitamins.."do I really have to?"

Most doctors test folates, B12, vitamins A, D and K. This is the standard Blood test. My doctor tests me for:
E
biotin
niacin
thiamin.

Every 2 years I have had full 32 level chemistry panel as well. This tests everything - even prostate levels if I were a Guy! - but for the bariatric issue it picks up

protein totals - globulin and albumin
magnesium
calcium
potassium

I have blood panels done twice a year - some of these vitamins are fat soluable since my digestive track is no longer normal and I am not sure what I absorb I don't take risks. Any med that can build up in my body is carefully monitored - as are dosages. Theraputic levels for me can be different for me than the norm.