At-home vitamin deficiency tests are available from online retailers, including LetsGetChecked, Everlywell, MyLab Box, and more. Popular test kits can measure a person’s vitamin D, B12, or iron levels ...

There are two forms of vitamin D in the blood: 25-hydroxy vitamin D, or calcidiol, and 1,25-dihydroxy vitamin D, or calcitriol. Tests will measure the amount of 25-hydroxy vitamin D in the blood. This ...

Two new lab tests to measure blood levels of vitamin D are inaccurate more than 40% of the time, according to a new study. Researchers say newer tests tend to overestimate the number of people who are ...

Some vitamin D tests may give misleading results despite progress made in recent years to improve the quality of these assays, according to the US Centers for Disease Control and Prevention (CDC).

Vitamin D tests certified by the U.S. Centers for Disease Control and Prevention (CDC) Clinical Standardization Programs (CSP) are well calibrated overall, according to a new study presented Sunday at ...

High doses of the vitamin biotin in a person's blood can cause errors in some medical lab tests, and these faulty test results have already been linked to one death, according to the U.S. Food and ...