Prolonged bedrest decreases which serum protein?

• A. Albumin
• B. Globulin
• C. Fibrinogen
• D. Transferrin

Answer: (A)

Prolonged bedrest promotes a catabolic state with reduced nutritional intake, so body protein stores are broken down and hepatic protein synthesis can lag behind demand. Albumin is the main circulating protein with a relatively long half-life, reflecting longer-term protein status; when protein intake is insufficient and catabolism is increased, albumin levels fall. In contrast, fibrinogen is a positive acute‑phase reactant and tends to rise with stress or inflammation, transferrin decreases more in inflammatory states or iron deficiency but is less specifically linked to immobility, and globulins are less consistently affected. Thus, the decrease most characteristic of prolonged bedrest is albumin.