RBC indices
Erythrocyte indices; Blood indices; Mean corpuscular hemoglobin (MCH); Mean corpuscular hemoglobin concentration (MCHC); Mean corpuscular volume (MCV); Red blood cell indices
Red blood cell (RBC) indices are part of the complete blood count (CBC) test. They are used to help diagnose the cause of anemia, a condition in which there are too few red blood cells.
Complete blood count
A complete blood count (CBC) test measures the following:The number of red blood cells (RBC count)The number of white blood cells (WBC count)The tota...
The indices include:
- Average red blood cell size (MCV)
-
Hemoglobin
amount per red blood cell (MCH)
Hemoglobin
Hemoglobin is a protein in red blood cells that carries oxygen. The hemoglobin test measures how much hemoglobin is in your blood.
- The amount of hemoglobin relative to the size of the cell (hemoglobin concentration) per red blood cell (MCHC)
How the Test is Performed
A blood sample is needed.
Blood sample
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
How to Prepare for the Test
No special preparation is necessary.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
Hemoglobin transports oxygen. RBCs carry hemoglobin and oxygen to our body's cells. The RBC indices test measures how well the RBCs do this. The results are used to diagnose different types of anemia .
Anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Different type...
Normal Results
These test results are in the normal range:
- MCV: 80 to 100 femtoliter
- MCH: 27 to 31 picograms/cell
- MCHC: 32 to 36 grams/deciliter (g/dL) or 320 to 360 grams per liter (g/L)
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your health care provider about the meaning of your specific test results.
What Abnormal Results Mean
These test results indicate the type of anemia:
-
MCV below normal. Microcytic anemia (may be due to low iron levels, lead poisoning, or
thalassemia
).
Thalassemia
Thalassemia is a blood disorder passed down through families (inherited) in which the body makes an abnormal form of hemoglobin. Hemoglobin is the p...
-
MCV normal. Normocytic anemia (may be due to sudden blood loss, long-term diseases,
kidney failure
,
aplastic anemia
, or man-made heart valves).
Kidney failure
Acute kidney failure is the rapid (less than 2 days) loss of your kidneys' ability to remove waste and help balance fluids and electrolytes in your b...
Aplastic anemia
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Normally, red ...
-
MCV above normal. Macrocytic anemia (may be due to low folate or B12 levels, or
chemotherapy
).
Chemotherapy
The term chemotherapy is used to describe cancer-killing drugs. Chemotherapy may be used to:Cure the cancerShrink the cancerPrevent the cancer from ...
- MCH below normal. Hypochromic anemia (often due to low iron levels).
- MCH normal. Normochromic anemia (may be due to sudden blood loss, long-term diseases, kidney failure, aplastic anemia, or man-made heart valves).
- MCH above normal. Hyperchromic anemia (may be due to low folate or B12 levels, or chemotherapy).
Risks
Veins and arteries vary in size from one person to another, and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood buildup under the skin)
- Infection (a slight risk any time the skin is broken)
References
Bunn HF. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 158.
Goljan EF. Red blood cell disorders. In: Goljan E, ed. Rapid Review Pathology . 4th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 12.
Review Date: 3/13/2016
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.