What Is a CBC Blood Test?

A CBC blood test is a type of blood test that renders a complete blood count. This test is useful in detecting a range of different medical problems and determining overall health status. Abnormal readings in the various cell counts measured by the test can reveal various medical problems that may require more scrutiny by a primary care provider, as stated by the Mayo Clinic.

A CBC measures different components of the blood, including red blood cells that carry oxygen and white blood cells that fight off infection within the body. A CBC also measures hematocrit, which is the proportion of plasma, the fluid component in blood for red blood cells. Hemoglobin that carries oxygen within the red blood cells is also measured, along with platelets that are responsible for clotting the blood, as mentioned by the Mayo Clinic.

A blood smear test may also be ordered along with a CBC. A blood smear test is useful in diagnosing certain blood disorders, including sickle cell disease, malaria and leukemia. A smear test accompanying a CBC allows the lab to examine the size, shape and number of various cells under a microscope with the help of a special dye, as noted by WebMD.