[Polycythemia resulting from abnormal hemoglobin with increased affinity for oxygen. Two cases (author's transl)].

An abnormal hemoglobin with increased oxygen affinity has to be suspected in all the cases of polycythemia where no direct signs of "polycythemia vera", or any of the classical reasons for erythropoietic stimulation can be demonstrated. This fact is documented by two new observations, one concerning a 44 year-old man with Hb Kempsey, another concerning a 58 year-old woman with Hb Malmö. The diagnosis is based on a scrupulous electrophoretic study involving an isoelectric focusing on polyacrylamide gel, and, on the study of the oxygen binding properties of the red blood cells. This polycythemia being a compensatory mechanism allowing a normal oxygen delivery to the tissues has to be respected and a compromise must be found with the cardiovascular risk.