Complete blood count.
A complete blood count (CBC) is a set of medical laboratory tests that provide information about the cells in a person's blood. The CBC indicates the counts of white blood cells, red blood cells and platelets, the concentration of hemoglobin, and the hematocrit (the volume percentage of red blood cells). The CBC is often carried out as part of a medical assessment, and can be used to monitor health or diagnose diseases. The results are interpreted by comparing them to reference ranges, which vary with gender and age. A landmark in the automation of blood cell counts was the Coulter principle (1953), which uses electrical impedance measurements to count blood cells and measure their sizes. This technology remains in use in many automated analyzers. Further research in the 1970s involved the use of optical measurements to count and identify cells, which enabled the automation of the white blood cell differential.
