A vitamin D blood test is not considered a routine procedure by most doctors today; in fact, these tests are rarely recommended. However, increasing evidence indicates that this might be one of the most important indicators of your overall health that you could find.

Numerous studies in recent years have shown that the overwhelming majority of the population suffers from vitamin D deficiency. Low vitamin D levels are now known to be at the root of many chronic illnesses. Since most of these health problems are very complex, and take many years to manifest, the connection between them and a vitamin D deficiency has been ignored for a very long time. Dr. Michael F. Holick, one of the world's leading vitamin D experts, says, "We estimate that vitamin D deficiency is the most common medical condition in the world."

Why Would You Need a Vitamin D Blood Test?

Unless you practice regular sunbathing in the summertime, and take vitamin D supplements the rest of the year, you almost certainly have low vitamin D levels in your bloodstream. You can't really determine this for sure without a vitamin D blood test.

You can arrange a vitamin D blood test with your health care provider, or order an inexpensive home blood test. Make sure you get the correct test. There are two vitamin D tests currently being offered: 1,25(OH)D, and 25(OH)D. The correct test to order is 25(OH)D, also called 25-hydroxyvitamin D, which is the better indicator of overall D status.

Make sure that your healthcare provider orders the correct test. Surprising as it may seem, many doctors are unfamiliar with the different vitamin D tests, and even if they order the right test, few of them know how to correctly interpret the results! A doctor who is not up to date with current studies might think anywhere from 20-50 ng/ml (nanograms per milliliter) is a normal vitamin D level, but that standard is terribly outdated. Make sure you get the results and interpret them for yourself.

Interpreting Your Vitamin D Blood Test

A normal vitamin D level has traditionally been set at between 20-56ng/ml (nanograms per milliliter). However, more recent studies have indicated that anything less than 50ng/ml should be considered deficient.

Current guidelines for vitamin D blood levels are:

Deficient: lower than 50ng/ml

Optimal: between 50-65ng/ml

Excess: greater than 100ng/ml

This range applies for everyone; children, adolescents, adults and seniors. A normal vitamin D level should never be below 32 ng/ml, and any levels below 20 ng/ml are considered serious deficiency states, increasing your risk of as many as 16 different cancers and autoimmune diseases like multiple sclerosis and rheumatoid arthritis, just to name a few.

The body does not reliably begin storing vitamin D in fat and muscle tissue until blood levels get above 50 ng/ml. So, at levels below 50 ng/ml, the body uses up all its vitamin D, without leaving anything in reserve.

A Game Plan for Optimizing Your Vitamin D Blood Levels

Start supplementing with vitamin D for a couple of months before you have the vitamin D blood test. Dr. John Cannell of the Vitamin D Council suggests that you take 1,000 IU per 25 pounds of body weight as a starting vitamin D dosage. A person who weighs 150 pounds, for instance, would take 6,000 IU per day. Once you get the results of your vitamin D blood test, adjust your dose so your blood level is between 50-80 ng/ml, summer and winter.