Clinical Utilities
Vitamin A has two natural forms: retinol (A1) and 3-dehydroretinol (A2). The predominating circulating form of Vitamin A, all-trans-retinol, is taken up by the cells of the retina. There, after an 11-cis isomerization and dehydrogenation, the compound is used to produce photosensitive pigments such as rhodopsin. The other function of Vitamin A is related to reproduction and growth. Vitamin A deficiency results in poor dark adaptation or dark blindness that can progress to keratomalacia. Overdosage of Vitamin A leads to toxicity presenting in acute poisoning with abdominal pain, nausea, vomiting, dizziness, headaches, etc.; and in chronic overdosage with bone and joint pain, hair loss, dry lips, anorexia, hepatomegaly, etc. Vitamin A status can be assessed by measuring the fasting serum or plasma retinol levels.

CPT Codes
84590

Reference Range

Component Information

Name		VITAMIN A (RETINOL)
Method		HPLC
CPT Code		84590
Units		ug/dL
Ref Range		38-106
Reflex Reason

Collection Notes
Use plastic vial. Protect from light: use foil wrapping or amber 
tubes. Patient should not consume alcohol for 1 day prior to 
collection. Avoid hemolysis. 

Additional Comments
Also known as Retinol.