The Complete Blood Count (CBC) is usually calculated using an automated hematology analyzer.
Automated Analysis of Blood Cells
These analyzers count cells and gather data about their size and structure. According to provided information, the concentration of hemoglobin is measured, and the red blood cell indices are calculated from measurements of red blood cells and hemoglobin.
This automated process delivers a comprehensive analysis of various blood components.
Components Measured and Calculated
Here's a breakdown of what is typically included in a CBC and how some components are derived:
Red Blood Cell (RBC) Count
- Measurement: Directly counted by the analyzer.
- Significance: Indicates the number of red blood cells in a given volume of blood.
Hemoglobin (Hb)
- Measurement: Measured directly by the analyzer using spectrophotometry.
- Significance: Measures the amount of hemoglobin in a given volume of blood. Hemoglobin carries oxygen.
Hematocrit (Hct)
- Calculation: Often calculated by the analyzer based on RBC count and Mean Cell Volume (MCV).
- Significance: Represents the percentage of blood volume occupied by red blood cells.
Red Blood Cell Indices
These indices are calculated from the RBC count, hemoglobin, and hematocrit:
- Mean Corpuscular Volume (MCV): Measures the average size of red blood cells.
- Calculation: MCV = (Hct / RBC) x 10
- Mean Corpuscular Hemoglobin (MCH): Measures the average amount of hemoglobin inside a red blood cell.
- Calculation: MCH = (Hb / RBC) x 10
- Mean Corpuscular Hemoglobin Concentration (MCHC): Measures the average concentration of hemoglobin inside a red blood cell.
- Calculation: MCHC = (Hb / Hct) x 100
- Red Cell Distribution Width (RDW): Measures the variation in size of red blood cells. A high RDW indicates greater variation.
White Blood Cell (WBC) Count
- Measurement: Directly counted by the analyzer. A differential count may also be performed to identify and count the different types of white blood cells (neutrophils, lymphocytes, monocytes, eosinophils, and basophils).
- Significance: Indicates the number of white blood cells in a given volume of blood, useful for detecting infection or inflammation.
Platelet Count
- Measurement: Directly counted by the analyzer.
- Significance: Indicates the number of platelets in a given volume of blood, important for blood clotting.
