A densitometer tracing of the hemoglobin electrophoresis gel is made in order to quantitate the bands present. Below is a normal gel and its corresponding tracing.

Hemoglobin A is 98% and A2 is 1.5%. Notice that Hemoglobin F is usually present in small enough amounts that its tracing may blend into that of Hemoglobin A. A separate procedure may need to be performed if quantitation of HbF is important.