Yes you can get a blood test and thats how my Dr found I was Vitamin D deficient. I think the normal range is like 50 - 300 and I was 40. I was surprised when I read my PG multivitamins that Vitamin D of any kind wasn't included - so now take a D3 supplement.
Couldn't find anywhere on the Internet that mentions this link, although there are references to Vitamin D3 deficiency and lack of bone density.
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