Hi Compiler, - There is no universally agreed upon Standard (an "exact" number) used but the ranges used are usually somewhat similar. Since the greatest natural production of Vitamin D comes from exposure to the sun, "normal" levels can vary seasonally, particularly in more northern climates.
Here is ONE set of parameters that identifies "NORMAL" findings, generally defined as that actually found in most humans in a geographical area, but It also sets one organizations standard for "OPTIMAL" readings, considered by them to be best for optimal physical body functioning.
"Normal" vitamin d 25 hydroxy lab values are:
20-56 ng/ml or 50-140 nmol/L
Their suggestion for the lowest owest "Optimal" vitamin d 25 hydroxy values are:
45-50 ng/ml or 115-128 nmol/L
Notice that the Normal Vitamin D level is reported in two ways: ng/ml or nmol/l. Translated, these mean ‘nanograms per millileter’ and ‘nanomoles per liter’. Don’t get confused with these differences, they are exactly the same RATIOS of vitamin D to blood volume, but are reported in different volumes of measurement (much as if you reported your driving speed in miles per hour or kilometers per hour). Each just uses a different measuring ‘tool’. Also notice that the lowest optimal number is almost double the lowest normal Vitamin D level. This is a substantial difference.
I hope this helps! -
[email protected] (aka) az4peaks