If a plasma specimen is used instead of serum for serum protein electrophoresis, what extra fraction may appear?

If a plasma specimen is used instead of serum for serum protein electrophoresis, what extra fraction may appear?

• A. Prealbumin area
• B. Beta region
• C. Beta-gamma region
• D. Gamma region

Answer: (C)

The key idea is that plasma contains fibrinogen, while serum does not. Fibrinogen is a large protein that, in electrophoresis, migrates with the beta globulins and can produce a distinct additional band near the border between the beta and gamma regions. This extra fraction is seen only when plasma is used, not serum, because the fibrinogen is present in plasma and absent in serum. So the extra fraction appears in the beta-gamma region. The prealbumin area is part of the albumin region, the beta region is already a normal part of the pattern (without accounting for the extra fibrinogen band), and the gamma region represents gamma globulins; the unique extra band due to fibrinogen sits at the beta-gamma junction rather than in those other regions.

The key idea is that plasma contains fibrinogen, while serum does not. Fibrinogen is a large protein that, in electrophoresis, migrates with the beta globulins and can produce a distinct additional band near the border between the beta and gamma regions. This extra fraction is seen only when plasma is used, not serum, because the fibrinogen is present in plasma and absent in serum.

So the extra fraction appears in the beta-gamma region. The prealbumin area is part of the albumin region, the beta region is already a normal part of the pattern (without accounting for the extra fibrinogen band), and the gamma region represents gamma globulins; the unique extra band due to fibrinogen sits at the beta-gamma junction rather than in those other regions.