A flat gamma curve on serum protein electrophoresis is most closely associated with which condition?

• A. Hypogammaglobulinemia
• B. Hypergammaglobulinemia
• C. Polyglobulinemia
• D. Monoclonal gammopathy

Answer: (A)

Gamma globulins are the antibodies circulating in serum. A flat gamma curve means there is very little or no gamma globulin present, indicating hypogammaglobulinemia. In serum protein electrophoresis, increased gamma region points to hypergammaglobulinemia, a broad, diffuse elevation (polyclonal gammopathy) to multiple antibody responses, or a sharp narrow spike (monoclonal gammopathy) from a single clone. The absence or near absence of the gamma peak specifically matches a deficiency in immunoglobulins, i.e., hypogammaglobulinemia.