What is a complete blood count (CBC) used to measure?

A complete blood count (CBC) is a comprehensive test that evaluates the components and characteristics of blood. It provides critical information about the various cells that make up the blood, including red blood cells, white blood cells, and platelets. The CBC measures aspects such as the number of each type of blood cell, hemoglobin levels, hematocrit (the proportion of blood volume that is occupied by red blood cells), and other parameters, which are essential for assessing a person's overall health and diagnosing various medical conditions.

While the concentration of electrolytes, blood sugar levels, and oxygen levels may be important indicators of health, these are not measured by a CBC. Instead, they require specific tests such as basic metabolic panels for electrolytes, glucose testing for blood sugar, and arterial blood gas analysis for oxygen levels. The CBC's focus on the different components of blood makes it a vital tool in medical diagnostics, enabling healthcare providers to identify issues such as anemia, infection, and other hematological conditions.