Blood cells carry many nutrients, wastes, and good and bad microorganisms to nearly all parts of the body. Main components are plasma, the yellowish clear liquid portion which acts as the transport medium for the circulation of nutritive substances, and the solid components such as red and white blood cells and platelets. These elements are measured against specific standardized parameters in healthy adults. Variations provide clues to imbalances and diseases in the patient. Healthy red blood cells are round discs, each with a depression in the center, which are not clumped together.
Normal levels vary with age, sex, and geographic location such as high altitude.
The count is usually done electronically. An over abundance of red blood cells can indicate a condition known as polycythemia, and too few, anemia. Hematocrit measures the percent of packed red blood cells. Normal values vary with sex, age and weight. They are responsible for producing antibodies which look for and destroy specific foreign antigens.