Red Blood Cell (RBC) Count

Evaluate anemia and loss of red cells and suspected polycythemic condition.

Presence of cold agglutinins may result in falsely low RBC counts.

Decrease in RBC count may be the result of red cell loss by bleeding or hemolysis (intravascular or extravascular), failure of marrow production (due to a broad variety of causes), or may be secondary to dilutional factors (eg, intravenous fluids). Increase in RBC count may be the result of primary polycythemia (polycythemia vera) or secondary polycythemia (hypoxemia of lung or cardiovascular disease, increased erythropoietin production associated with renal cyst, renal cell carcinoma, cerebellar hemangioblastoma, or high O2 affinity hemoglobinopathy) including stress polycythemia (hemoconcentration associated with exercise, exertion, fright, etc).