Diagnostic Approach to Erythrocytosis

Essential Laboratory Evaluation

• Obtain a complete blood count (CBC) with white blood cells, hemoglobin, and platelets to assess bone marrow function, as recommended by the National Kidney Foundation, in patients with suspected erythrocytosis 1, 2, 3
• Measure arterial oxygen saturation via ABG or reliable pulse oximetry to exclude occult hypoxemia as a driver of compensatory erythrocytosis, as suggested by the American Heart Association 4, 5
• Measure serum EPO level to differentiate between EPO-driven (secondary) and EPO-independent (primary) erythrocytosis, according to the European Renal Association 1, 2
• Check serum creatinine and calculate estimated glomerular filtration rate (eGFR) to assess renal function, as recommended by the National Kidney Foundation 1, 2, 3

Additional Targeted Testing

• Obtain serum ferritin and transferrin saturation to assess iron status, as suggested by the American Heart Association 1, 2, 3
• Consider carboxyhemoglobin level if there is any smoking history, as recommended by the Centers for Disease Control and Prevention 3

When to Refer to Hematology

• Refer to hematology if EPO level is low or inappropriately normal for the degree of erythrocytosis, as suggested by the American Society of Hematology 4
• Refer to hematology if multiple cell lines are abnormal on CBC, according to the National Comprehensive Cancer Network 1, 2
• Refer to hematology if no secondary cause is identified after the above workup, as recommended by the European Hematology Association 4