The Carlson Vitamin D Test Kit is a simple, at-home finger prick test that measures the amount of D3 in our blood by the gold standard LC-MS/MS method. Vitamin D blood levels in the range of 30-100 ng/mL have been associated with bone, immune, brain, and heart health. Results are sent within two to four weeks. Once we know our vitamin D levels, we can make diet and lifestyle modifications to improve our levels in as little as a few months (if needed).