Other testsReported in ng/mLVitamin D (25-hydroxyvitamin D)
The storage form of vitamin D. It is the measurement used to judge whether vitamin D status is low, typical, or high.
What it measures
Skin makes vitamin D in sunlight, and food and supplements add more. The liver converts it to 25-hydroxyvitamin D, which circulates for weeks and is the level this panel reports. Kidneys later activate a portion of it. Because the storage form is stable, this result reflects weeks of sun, diet, and supplements, not what you ate this morning. Adult results on this panel are typically interpreted against 30–100 ng/mL.
Why it is on the panel
Low vitamin D is common, especially in winter, in people with darker skin, in people who cover their skin, and in people with limited sun. It affects calcium absorption, bone, and muscle. A high level usually means supplements have gotten ahead of need. Either result connects to the calcium and phosphorus on this panel.
How to read it
Use the adult bands as a map, then look at calcium, phosphorus, and alkaline phosphatase. Low vitamin D with a low or low-normal calcium is a coherent story. A high vitamin D with a high calcium is a reason to stop extra supplements and talk with a clinician. Levels are often lower in late winter.
When it runs higher
Supplements are the usual cause of a high 25-hydroxyvitamin D. Results above 100 ng/mL are above this panel’s adult interval. Very high levels, especially with a high calcium, can cause thirst, constipation, and kidney stones. More supplement is the wrong response to a level that is already high.
When it runs lower
Limited sun, low intake, malabsorption, and higher body weight are common reasons for a low level. Status is often described as deficient under 20 ng/mL and insufficient from 20 to 29 ng/mL. Bone discomfort and muscle weakness can accompany a true deficiency. How much to take is a clinician’s recommendation, based on the level, not a number this page can set.
Same group
Other Other tests
How to use this page
This page explains what the measurement is for. It is educational. Your Healiam report includes the reference interval for your age and sex, and a clinician reads that result with your history, medicines, and the rest of the panel. Talk with a clinician before changing diet, supplements, or treatment because of a number on a report.
Vitamin D
Vitamin D is part of the full panel.
No referral or insurance required.
One preventive draw covers this measurement and the rest of the Healiam panel. CLIA-certified results come back in days.