Normal and abnormal Hb can be detected by electrophoresis, which matches hemolyzed RBC material against standard bands for the various Hb types known. The most common forms of normal adult Hb are HbA₁, HbA₂, and Hb F. Of the various types of abnormal Hb (hemoglobinopathies), the best known are Hb S (responsible for sickle cell anemia) and Hb C (results in a mild hemolytic anemia). The most common abnormality is a significant increase in HbA₂, which is diagnostic of the thalassemias, especially beta-thalassemia trait. More than 350 variants of Hb have been recognized and identified.

HbA₁: 96.5%–98.5% or 0.96–0.985 mass fraction

HbA₂: 1.5%–3.5% or 0.015–0.035 mass fraction

Hb F: 0%–1% or 0–0.01 mass fraction