Vitamin D Test — Information
The usual test for vitamin D status is a blood test called 25-hydroxyvitamin D [25(OH)D]. It is the best routine measure of vitamin D levels in the body.
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MedlinePlus
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What does the test measure?
It measures the amount of vitamin D in your blood, usually reported as:
ng/mL (nanograms per millilitre), or
nmol/L (nanomoles per litre)
Conversion: 1 ng/mL = 2.5 nmol/L.
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Office of Dietary Supplements
How to interpret the result
A commonly used NIH/NASEM reference is:
25(OH)D result General interpretation
<12 ng/mL (<30 nmol/L) Deficiency
12–<20 ng/mL (30–<50 nmol/L) Generally inadequate
≥20 ng/mL (≥50 nmol/L) Adequate for most people
>50 ng/mL (>125 nmol/L) Potentially too high
Different laboratories and medical organizations may use somewhat different reference ranges, so your lab's range and your clinical situation matter.
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Office of Dietary Supplements
Do you need fasting?
Usually, no. A vitamin D blood test generally does not require fasting, although you should follow any specific instructions from your laboratory or doctor.
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MedlinePlus
When might a doctor order it?
Testing may be considered if there is concern about vitamin D deficiency, such as with bone pain, muscle weakness, osteoporosis/low bone density, limited sun exposure, malabsorption problems, or certain kidney/liver conditions or medications. Routine testing of every healthy adult is not generally recommended.
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MedlinePlus
Important: Don't take high-dose vitamin D on your own based only on a test result. Excess vitamin D can raise blood calcium and potentially damage the kidneys and other tissues.
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MedlinePlus
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If you have your Vitamin D report, send me the 25-OH Vitamin D value and unit (ng/mL or nmol/L), and I can explain what your result means.in nidan pathology laboratory @location
