Diagnosis of hemoglobinopathy and β-thalassemia by 21-Tesla Fourier transform ion cyclotron resonance mass spectrometry

Hemoglobin is the oxygen-transport protein in red blood cells consisting of four globulins. Human adult hemoglobin A (HbA), containing two identical α-chains (141 amino acids, 15,126.4 Da) and two identical β-chains (146 amino acids, 15,867.2 Da), accounts for around 97% of the total hemoglobin in a normal adult, whereas HbA2, with two α-chains and two delta-chains, accounts for 1.5–3.5% of the total hemoglobin in normal adults. Moreover, the proportions of HbA, HbA2, and HbF can fluctuate during human development from the fetal to adult stage.