Complete Blood Count (CBC) Test for MCV, MCHC, and Other Red Blood Cell Indices
To request MCV, MCHC, and other red blood cell indices, you should order a Complete Blood Count (CBC) test. 1 This is the standard laboratory test that provides these parameters along with other important hematologic measurements.
What a CBC Test Includes
A CBC test provides comprehensive information about blood cells, including:
Red Blood Cell (RBC) Count: Number of red blood cells per volume of blood
Hemoglobin (Hb): Oxygen-carrying protein in red blood cells
Hematocrit (Hct): Percentage of blood volume occupied by red blood cells
Red Blood Cell Indices:
- Mean Corpuscular Volume (MCV): Average size of red blood cells
- Mean Corpuscular Hemoglobin (MCH): Average amount of hemoglobin per red blood cell
- Mean Corpuscular Hemoglobin Concentration (MCHC): Average concentration of hemoglobin in a given volume of red blood cells
- Red Blood Cell Distribution Width (RDW): Measure of variation in red blood cell size
White Blood Cell (WBC) Count: Total number of white blood cells
Platelet Count: Number of platelets per volume of blood
Clinical Utility of Red Blood Cell Indices
The red blood cell indices (MCV, MCH, MCHC) are particularly useful for:
- Classifying anemias: These parameters help distinguish between different types of anemia 1
- Diagnosing iron deficiency: Low MCV, MCH, and MCHC values may indicate iron deficiency anemia 2
- Identifying thalassemias: Very low MCV (<70 fl) with normal RDW is suggestive of thalassemia trait 1
- Detecting chronic disease: Normal/low MCV with normal/elevated ferritin may indicate anemia of chronic disease 1
Diagnostic Accuracy of Red Blood Cell Indices
The diagnostic accuracy of these parameters varies:
For iron deficiency anemia, studies show moderate diagnostic accuracy with areas under the ROC curve of:
- 0.71 for hemoglobin
- 0.67 for MCH
- 0.71 for MCHC
- 0.73 for RDW 2
These parameters are more accurate in diagnosing iron deficiency anemia than iron deficiency without anemia 3
When to Order a CBC
A CBC should be ordered:
- As part of routine health assessment
- When evaluating symptoms of anemia (fatigue, pallor, shortness of breath)
- When monitoring known hematologic disorders
- At least annually in patients with chronic kidney disease 1
- More frequently (every 3-6 months) in patients with unstable clinical course or evidence of previous hemoglobin decline 1
Interpretation Considerations
When interpreting CBC results, be aware that:
- Normal values of MCV, MCH, and MCHC do not exclude iron deficiency in anemic patients 3
- Additional testing (serum ferritin, transferrin saturation) may be needed to confirm iron deficiency 1
- The diagnostic accuracy of these parameters may vary by age and clinical context 3
In summary, when you need to assess MCV, MCHC, and other red blood cell parameters, ordering a Complete Blood Count (CBC) is the appropriate laboratory test to request.