Beta-gamma bridging only on electrophoresis is most associated with which plasma component?

• A. Plasma (fibrinogen)
• B. IgA
• C. IgM
• D. C-reactive protein

Answer: (A)

Beta-gamma bridging on electrophoresis occurs when a large amount of a beta-region–migrating plasma protein is present and creates a continuous connection with the gamma region. The protein that causes this specific pattern is fibrinogen, which is a plasma protein. Fibrinogen is removed during serum preparation, so this bridging doesn’t appear in serum samples. That’s why this pattern is associated with plasma. IgA and IgM rise in the gamma or other regions but don’t produce the beta-gamma bridge, and C-reactive protein rises as an acute-phase reactant without creating this distinct bridging pattern.