Vitamin A

The Vitamin A, Serum (retinol) test is used to assess vitamin A status when deficiency or excess is suspected. It supports the differential diagnosis of hypervitaminosis A and informs evaluation of nutritional adequacy. When both serum carotene and vitamin A concentrations are reduced, the pattern supports inadequate vitamin A nutrition.

Retinol, the measurable form of vitamin A in serum, is quantified by LC–MS/MS to provide an index of vitamin A status. Vitamin A participates in vision, preservation of epithelial tissues, immune responsiveness, and growth. Low levels occur with inadequate intake or malabsorption. Measured retinol concentrations are also used in the differential evaluation of hypervitaminosis A. Concurrent decreases in serum carotene and vitamin A support a diagnosis of inadequate vitamin A nutrition.