Red Blood Cell Count (RBC)
|See Also||Lab Tests|
The test is a count of the number of circulating red blood cells. Normally RBCs survive in the peripheral blood for approximately 120 days. Intravascular RBC trauma, such as that caused by artificial heart valves or atherosclerosis can shorten the lifespan of RBCs. Conditions such as an enlarged spleen, portal hypertension or leukemia may destroy RBCs and decrease the number in the peripheral circulation.
- Fasting is not required for this test.
- Women tend to have lower values than men.
- Normal RBC levels decrease during pregnancy.
- Living in high altitudes may increase RBC levels.
- Drugs that may cause increased levels include gentamicin and methyldopa.
- Drugs that may cause decreased levels include chloramphenicol, hydantoins and quinidine.
RBC count is primarily used as a test for anaemia, but it can also indicate:
High levels indicate:
- Congenital heart disease
- Severe chronic obstructive pulmonary disease (COPD)
- Polycythemia vera
- Severe dehydration
Low levels indicate:
- Anaemia including hemolytic anemia
- Dietary deficiency
- Bone marrow failure
- Renal disease
- Normal pregnancy
- Collagen vascular diseases such as rheumatoid arthritis or lupus
- Multiple myeloma
- Hodgkin disease
- Pagana Kathleen D, Pagana Timothy J (2006) Mosby's Manual of Diagnostic and Laboratory Tests, Mosby.
- Weatherby Dicken, Ferguson Scott (2002) Blood Chemistry and CBC Analysis: Clinical Laboratory Testing from a Functional Perspective, Bear Mountain.