RBC count

Alternative names:

erythrocyte count; red blood cell count

Normal values:

RBC (varies with altitude):

• male: 4.7 to 6.1 million cells/mcl
• female: 4.2 to 5.4 million cells/mcl

Note: cells/mcl = cells per microliter

What abnormal results mean:

Abnormal RBCs have a shorter life span. Intravascular RBC trauma, such as that caused by artificial heart valves or peripheral vascular (blood vessel) atherosclerotic plaques can damage RBCs. An enlarged spleen such as that caused by portal hypertension or leukemia may remove normal red cells as well as senescent (aging) ones.

High numbers of RBCs may indicate:
Low oxygen tension in the blood from:

• congenital heart disease
• cor pulmonale
• pulmonary fibrosis
• polycythemia vera
• dehydration (such as from severe diarrhea)
• kidney disease with high erythropoietin production

Low numbers of RBCs may indicate:
blood loss from:

• anemia (various types)
• hemorrhage (bleeding)
• bone marrow failure (for example, from radiation, toxin, fibrosis, tumor)
• erythropoietin deficiency (secondary to renal disease)
• hemolysis (RBC destruction) from transfusion reaction
• leukemia
• multiple myeloma
• malnutrition

nutritional deficiencies of:

• iron
• folate
• vitamin B12
• vitamin B6
• overhydration

Additional conditions under which the test may be performed:

• Alport syndrome
• hemolytic anemia due to G6PD deficiency
• idiopathic autoimmune hemolytic anemia
• immune hemolytic anemia
• macroglobulinemia of Waldenstrom
• paroxysmal nocturnal hemoglobinuria (PNH)
• primary myelofibrosis
• renal cell carcinoma
• drug-induced immune hemolytic anemia