BACKGROUND: High oxygen-affinity haemoglobin variants and 2,3-diphosphoglycerate (2,3-DPG) deficiency are inherited diseases generating low tissue oxygen tension and erythropoietin-driven erythrocytosis, that characterizes the clinical phenotype of patients. Level of blood p50 (the oxygen tension at which haemoglobin is 50% saturated) is used to recognize these conditions. OBJECTIVES: To define the clinical utility of blood p50 measurement in the diagnosis of isolated erythrocytosis. SUBJECTS AND DESIGN: Venous blood p50 measurement was included in the diagnostic work-up of 102 consecutive patients with isolated erythrocytosis besides blood cell count, arterial oxygen saturation, serum erythropoietin measurement and screening for JAK2 mutations. SETTING: Haematological Outpatient Section at University Hospital. RESULTS: Seven patients had relative erythrocytosis. Among 95 patients with absolute erythrocytosis, 4 (4.2%) had decreased p50 level. The extended study of family members revealed a familial inheritance. Two families had haemoglobin variants already described as Haemoglobin Malmö and Haemoglobin San Diego. In one family, the proband had a new high oxygen-affinity haemoglobin variant (Haemoglobin Safi) resulting from the transversion C-->A at codon 81 of the alpha2-globin gene. In the last family, a deficiency of 2,3-DPG was found. Within the 91 patients with normal p50 values, 46 (51%) had secondary erythrocytosis, 13 (14%) polycythemia vera and 32 (35%) idiopathic erythrocytosis. CONCLUSIONS: This study suggests that the investigation of blood p50 level may be useful to define diagnosis in patients with isolated erythrocytosis.
BACKGROUND: High oxygen-affinity haemoglobin variants and 2,3-diphosphoglycerate (2,3-DPG) deficiency are inherited diseases generating low tissue oxygen tension and erythropoietin-driven erythrocytosis, that characterizes the clinical phenotype of patients. Level of blood p50 (the oxygen tension at which haemoglobin is 50% saturated) is used to recognize these conditions. OBJECTIVES: To define the clinical utility of blood p50 measurement in the diagnosis of isolated erythrocytosis. SUBJECTS AND DESIGN: Venous blood p50 measurement was included in the diagnostic work-up of 102 consecutive patients with isolated erythrocytosis besides blood cell count, arterial oxygen saturation, serum erythropoietin measurement and screening for JAK2 mutations. SETTING: Haematological Outpatient Section at University Hospital. RESULTS: Seven patients had relative erythrocytosis. Among 95 patients with absolute erythrocytosis, 4 (4.2%) had decreased p50 level. The extended study of family members revealed a familial inheritance. Two families had haemoglobin variants already described as Haemoglobin Malmö and Haemoglobin San Diego. In one family, the proband had a new high oxygen-affinity haemoglobin variant (Haemoglobin Safi) resulting from the transversion C-->A at codon 81 of the alpha2-globin gene. In the last family, a deficiency of 2,3-DPG was found. Within the 91 patients with normal p50 values, 46 (51%) had secondary erythrocytosis, 13 (14%) polycythemia vera and 32 (35%) idiopathic erythrocytosis. CONCLUSIONS: This study suggests that the investigation of blood p50 level may be useful to define diagnosis in patients with isolated erythrocytosis.
Authors: Melanie J Percy; Nauman N Butt; Gerard M Crotty; Mark W Drummond; Claire Harrison; Gail L Jones; Matthew Turner; Jonathan Wallis; Mary Frances McMullin Journal: Haematologica Date: 2009-09 Impact factor: 9.941
Authors: Kevin L Webb; Paolo B Dominelli; Sarah E Baker; Stephen A Klassen; Michael J Joyner; Jonathon W Senefeld; Chad C Wiggins Journal: Front Physiol Date: 2022-01-14 Impact factor: 4.755