Retinol-binding protein (RBP) in serum/plasma

Why This Test Matters

Retinol-binding protein (RBP) is a small protein in your blood that carries vitamin A, a fat-soluble nutrient essential for vision, immune function, and cell growth. It’s produced in the liver and helps transport vitamin A to tissues. RBP levels can reflect liver health and vitamin A status, making this test useful in diagnosing conditions like liver disease or vitamin A deficiency.

How the Test Works

Your blood sample is tested using an immunoassay method to detect and quantify RBP. This method identifies the protein’s presence and concentration without measuring vitamin A directly.

Common Reasons for Testing

Doctors may order this test if you have symptoms of liver disease (e.g., fatigue, jaundice), vitamin A deficiency, or if other blood tests suggest liver or nutritional issues. It can also be part of a broader evaluation for malabsorption disorders or metabolic conditions.

What to Expect Before the Test

No special preparation is needed, but avoid alcohol for 24 hours before testing to ensure accurate results. Fasted or non-fasted blood draws are typically acceptable, but check with your provider if you have questions.