In the hemoglobin electrophoresis assay all Hb isoforms are

In the hemoglobin electrophoresis assay, all Hb isoforms are measured relative to HbA position on the gel in this assay. Can you think why this might be a good way to measure Rf value for this assay? Hint several possible answers here.. think about cell biology concepts, macromolecule structure, and sample source.

The reason for HbA to be considered as a relative for measurements of other Hb isoforms include-