What does a Hematocrit test measure?

A Hematocrit test specifically measures the proportion of red blood cells (RBCs) in the blood. It is expressed as a percentage, indicating how much of the blood volume is occupied by these cells. This measurement is crucial for assessing a person's overall blood health and can aid in diagnosing various conditions, such as anemia, polycythemia vera, and other blood disorders.

The focus on RBCs is important because their levels directly affect the blood's ability to carry oxygen throughout the body. Abnormal hematocrit levels can indicate issues such as dehydration, nutritional deficiencies, or chronic diseases impacting red blood cell production or lifespan.

Other choices do not define what the Hematocrit test assesses. The percentage of blood made up of white blood cells (WBCs) is related to the immune response, the percentage of plasma pertains to liquid components carrying nutrients, hormones, and waste, and blood glucose levels relate to metabolic functions, none of which are measured by a Hematocrit test.