Select the correct order of hemoglobin migration on citrate agar at pH 6.2.

The correct order of hemoglobin migration on citrate agar at pH 6.2 is significant in understanding the electrophoretic mobility of different hemoglobin types. At this pH, the various hemoglobin variants exhibit distinct charges that affect how they migrate through the gel.

Hemoglobin F (fetal hemoglobin) has the highest mobility in this context, as it carries a positive charge which makes it migrate the furthest towards the anode. After hemoglobin F, the next one is hemoglobin A, which has a lower positive charge compared to fetal hemoglobin but still moves towards the anode.

Following hemoglobin A, hemoglobin S (the variant commonly associated with sickle cell disease) has a charge that is less positive than hemoglobin A, causing it to migrate more slowly. Finally, hemoglobin C, which is more negatively charged than the others, moves the least distance toward the anode.

Thus, the correct order of migration on citrate agar at pH 6.2 is from fetal hemoglobin to hemoglobin A, then to hemoglobin S, and finally to hemoglobin C, supporting the answer provided. This knowledge is essential for understanding the electrophoretic patterns seen in clinical laboratory testing for hemoglobinopathies