QuestAssureD™ for Infants, 25-Hydroxyvitamin D Test
This test measures 25-Hydroxyvitamin D in a serum sample from infants younger than three years old, using a method that separates out a substance that can otherwise raise results falsely. It can be ordered through Celio Health.
About this test
A 0.5 mL serum sample is analyzed using liquid chromatography-tandem mass spectrometry, which separates the c3-epimer, an inactive form of Vitamin D, from 25-Hydroxyvitamin D before measurement.
Quest notes that levels of the c3-epimer are usually negligible in older children and adults, so it does not typically cause falsely elevated results in those groups, and the assay produces accurate results on patients of any age. Quest lists this test under aliases including d3, 25-oh, sunshine vitamin, VIT D and Infants.
Test details
| Quest code | 91935 |
|---|---|
| Methodology | Chromatography/Mass Spectrometry |
| Sample type | 0.5 mL serum |
| Patient preparation | Fast before your blood draw if you can; water is fine. |
| Collection | Quest patient service center |
Related tests and panels
Quest resources
Additional details
What this test looks at
The test reports 25-Hydroxyvitamin D, broken out by the D2 and D3 forms and as a total, after the c3-epimer has been separated out by chromatography. Quest describes this separation as specifically indicated for infants younger than three years old, where the c3-epimer can otherwise cause a falsely elevated result on standard testing.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does this test measure?
It measures 25-Hydroxyvitamin D in a 0.5 mL serum sample, using chromatography and mass spectrometry to separate out the c3-epimer, an inactive form of Vitamin D.
How is the sample collected?
The test uses a 0.5 mL serum sample from a routine blood draw.
Do I need to prepare for this test?
Fast before your blood draw if you can; water is fine. This is the preparation Quest publishes for this test; if your clinician gives you different instructions, follow theirs.
Why is this different from a standard Vitamin D test?
Quest describes standard Vitamin D measurements in infants younger than three years old as sometimes falsely elevated by the c3-epimer. This assay separates that substance out, so it is specifically indicated for that age group.
Is this test accurate for older children or adults?
Quest notes that c3-epimer levels are usually negligible in older children and adults, so the assay produces accurate results on patients of any age.
How much is a Vitamin D QuestAssure for Infants, 25-Hydroxyvitamin D test?
$225, paid once at checkout. The price includes the physician's order this test requires and sample collection at a Quest patient service center.