Rapid and specific detection of clinically significant haemoglobinopathies using electrospray mass spectrometry-mass spectrometry

Increasing demand for population screening for the haemoglobinopathies gives rise to a requirement for high throughput systems, which allow for cost effective, rapid, sensitive and specific screening of clinically significant haemoglobins. We have developed a practical and efficient approach using tryptic digestion and electrospray triple quadrupole mass spectrometry-mass spectrometry (MSMS) in multiple reaction monitoring acquisition mode for the identification of the clinically important haemoglobin variants, S, C, D-Punjab, O-Arab, and E. A total of 200 blood samples, comprising 52 haemoglobin AA, 57 AS (sickle cell trait), 44 AC (C trait), 16 SC (SC disease), 14 SS (sickle cell disease), 10 AE (E trait), 2 AD(Punjab) (D-Punjab trait) and 1 each of AO(Arab) (O-Arab trait), CC (C disease), (DDPunjab)-D-Punjab (D-Punjab disease), (OOArab)-O-Arab (O-Arab disease), and EE (E disease), have been analysed in parallel with existing phenotype and molecular methods. All haemoglobin variants were correctly identified by MSMS, with no false positives or false negatives. The system detects both heterozygotes and homozygotes and has potential applications in neonatal and antenatal screening.