This blood test is ordered from Life Extension®. Their doctors prepare the test requests for you to take to a LabCorp location outside of Maryland for your blood draw. The test results go directly to you rather than to your doctor. Results are received quickly and the process is fairly smooth! The cost of this test is not going to be covered by insurance but submission to your FSA/HSA account is possible (not guaranteed). It might just be a PITA to try.
From Life Extension®:
Vitamin D is an essential nutrient. This simple 25-hydroxyvitamin D blood test can determine whether your levels fall within an optimal range.
Recent research has shown that vitamin D is important to every cell and tissue throughout the body. From proper immune function and bone density to heart health and mood disorders, vitamin D is critical for optimal health.
You should know your vitamin D blood level. Life Extension® offers a reliable vitamin D blood test at a fraction of what most commercial blood labs charge. Optimal blood levels of vitamin D are often far greater than the standard reference range. The only way to achieve an optimal level is through proper supplementation.