The general the range is as follows:

• Male: 4.7 to 6.1 million cells per microliter (cells/mcL)
• Female: 4.2 to 5.4 million cells/mcL

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Higher-than-normal numbers of RBCs may be due to:

• Cigarette smoking
• Congenital heart disease
• Cor pulmonale
• Dehydration (such as from severe diarrhea)
• Kidney tumor (renal cell carcinoma)
• Low blood oxygen levels (hypoxia)
• Pulmonary fibrosis
• Polycythemia vera

Your RBC count will increase for several weeks when you move to a higher altitude.

Drugs that can increase the RBC count include:

• Gentamicin
• Methyldopa

Lower-than-normal numbers of RBCs may be due to:

• Anemia
• Bone marrow failure (for example, from radiation, toxins, or tumor)
• Erythropoietin deficiency (secondary to kidney disease)
• Hemolysis (RBC destruction) due to transfusion, blood vessel injury, or other cause
• Hemorrhage (bleeding)
• Leukemia
• Malnutrition
• Multiple myeloma
• Nutritional deficiencies of:
  • Iron
  • Copper
  • Folate
  • Vitamin B-12
  • Vitamin B-6
• Overhydration
• Pregnancy

Drugs that can decrease the RBC count include:

• Chemotherapy drugs
• Chloramphenicol
• Hydantoins
• Quinidine