Electrophoresis of serum protein to detect alpha 1-antitrypsin deficiency: five illustrative cases.

We describe five cases of severe alpha 1-antitrypsin (AAT) deficiency to illustrate the importance of visual inspection of electrophoretic patterns of serum proteins. In four patients the diagnosis of AAT deficiency was clinically unsuspected; in the other patient, the electrophoretic pattern was the first clue to confirm the diagnosis. Densitometric scanning of these patterns invariably overestimated the concentration of alpha 1-globulin. By visually inspecting electrophoretic strips instead of relying on densitometry, clinical chemists can help detect AAT deficiency earlier.