To the Editor: Rai et al. (1 ) recently described an elegant method for detecting hemoglobin (Hb) variants that cause erythrocytosis, using electrospray mass spectrometry. Many of these variants are not detectable with conventional electrophoretic techniques. The authors also stated that “functional studies of oxygen saturation curves would be the ideal method to screen for Hb variants that cau...

Organisms living under aerobic conditions need oxygen for the metabolic conversion of nutrition into energy. With the appearance of increasingly complex animals, a specialized transport system (erythrocytes) arose during evolution to provide oxygen to virtually every single cell in the body. Moreover, in case of low environmental partial pressure of oxygen, the number of erythrocytes automatica...