EPO and polycythemia: There are two points that relate to erythropoietin: (a) It remains a question whether the elevation of erythropoietin appears before erythrocytosis or not, because some patients presented with erythrocytosis in the absence of elevated serum erythropoietin at the first clinic visit (17, 26); (b) A potential connection might exist between elevated erythropoietin and telangiectasias or intrapulmonary shunting.