High Performance Liquid Chromatography (HPLC)
Results may be elevated in women on oral contraceptives.
Vitamin A is critical for vision, growth, and many cell functions. High concentrations of vitamin A are seen with renal failure, but this is not associated with toxicity, and excessive ingestion. High concentrations are associated with bone fractures. Low concentrations of vitamin A are consistent with fat malabsorption and rarely due to inadequate diet. Vitamin A, vitamin E, and carotene are always extracted and detected simultaneously. This is a free vitamin A (retinol).