Retinol binding protein

Retinol binding protein (RBP) is produced by the liver and transports vitamin A (retinol) through the bloodstream to tissues. An RBP test measures this protein in blood to assess vitamin A status and liver function. Low RBP suggests vitamin A deficiency, malabsorption, or liver dysfunction. Elevated RBP may indicate kidney disease (as kidneys filter RBP) or liver disease. Since RBP reflects both vitamin A status and liver health, abnormal levels warrant further investigation. This test is useful for evaluating nutritional status, assessing causes of vision problems, and screening for organ dysfunction.