Introduction Red blood cell (RBC) indices are measurements that provide information about the size, shape, and quality of red blood cells. These indices are used to diagnose different types of anemia and other conditions that affect red blood cells.
Types There are four types of red blood cell indices: Mean corpuscular volume (MCV), Mean corpuscular hemoglobin (MCH), Mean corpuscular hemoglobin concentration (MCHC), and Red cell distribution width (RDW).
- Mean corpuscular volume (MCV) measures the average size of your red blood cells. It is used to classify red blood cells based on size.
- Mean corpuscular hemoglobin (MCH) measures the average amount of hemoglobin in a single red blood cell. Hemoglobin is a protein in red blood cells that carries oxygen.
- Mean corpuscular hemoglobin concentration (MCHC) also measures hemoglobin in red blood cells. In addition, it includes a calculation of the size and volume of your red blood cells.
- Red cell distribution width (RDW) measures differences in the volume and size of your red blood cells.
Calculations The calculations for these indices are as follows:
- MCV = (Hematocrit ÷ RBC count) × 10
- MCH = (Hemoglobin ÷ RBC count) × 10
- MCHC = (Hemoglobin ÷ Hematocrit) × 100
- RDW = (Standard deviation of MCV ÷ Mean MCV) × 100
Interpretation Abnormal results for these indices may indicate different types of anemia or other conditions that affect red blood cells. For example:
- A low MCV may indicate iron deficiency anemia or thalassemia.
- A high MCV may indicate vitamin B12 or folate deficiency anemia.
- A low MCH or MCHC may indicate iron deficiency anemia or thalassemia.
- A high RDW may indicate a mixed anemia or early stages of iron, vitamin B12, or folate deficiency anemia.
Normal Range The normal ranges for these indices may vary slightly from lab to lab. According to the American Association for Clinical Chemistry, normal values for RBC indices are:
- The MCV should be 80 to 96 femtoliters.
- The MCH should be 27 to 33 picograms per cell.
- The MCHC should be 33.4 to 35.5 grams per deciliter