What is the role of prealbumin (transthyretin) in nutrition assessment, and what are its limitations?

• A. Reflects long-term protein status and is unaffected by inflammation.
• B. Reflects short-term protein status and is affected by inflammation and liver function, limiting specificity.
• C. It is a perfect marker with no limitations.
• D. Measures vitamin levels.

Answer: (B)

Prealbumin (transthyretin) is a liver-made transport protein with a short half-life, so its serum level mirrors recent changes in protein intake and short-term nutritional status. Because of this rapid response, it can be useful for tracking how well a patient is responding to nutrition support over days. However, its usefulness is limited by inflammation and liver function. It behaves like a negative acute-phase reactant, so during acute inflammation its production drops and levels fall even if nutritional status hasn’t truly worsened, reducing specificity for malnutrition. Liver disease or impaired hepatic synthesis can also lower prealbumin independent of true protein adequacy, confounding interpretation. For these reasons, prealbumin should be interpreted alongside inflammatory markers (like CRP), albumin, anthropometric data, and the overall clinical picture, serving mainly as a short-term indicator rather than a standalone measure of nutritional status.