How to Read Your Vitamin D Test Report

Which Marker Is Being Tested

The vitamin D test on a checkup report is usually measuring 25-hydroxyvitamin D, the most commonly used indicator of the body's vitamin D reserves, reflecting the combined picture of dietary intake and sun-driven synthesis. The unit on your report might be ng/mL or nmol/L — roughly, 1 ng/mL equals about 2.5 nmol/L, so pay attention to which unit is being used.

Common Classification Thresholds (vary slightly by guideline and lab)

• Sufficient: generally considered to be 30 ng/mL (about 75 nmol/L) or above
• Insufficient: roughly 20–30 ng/mL
• Deficient: below 20 ng/mL (about 50 nmol/L)

Why Vegetarians Need to Pay Extra Attention

Vitamin D occurs naturally in relatively larger amounts in animal foods (such as egg yolks and fatty fish), so vegetarians who don't get enough sun exposure may face a somewhat higher risk of deficiency than the general population. If your results fall in the insufficient or deficient range, you can address it by spending more time in the sun, choosing fortified foods, or supplementing with vitamin D2/D3 under a doctor's guidance.

Testing Advice

Regular testing is advisable during winter months with less sunlight, for people who work indoors long-term, and for older adults. After starting vitamin D supplementation, it's generally best to retest after 2–3 months to evaluate the effect, rather than increasing the dose on your own over the long term. Vitamin D is fat-soluble, and prolonged excess intake can also cause problems such as abnormal blood calcium levels, so avoid stacking multiple supplements that duplicate your intake.