The human body is a complex organism which uses blood as its means of transporting various items across the body. Different parts of the body require different items and these are all made available by the blood. The blood transports nutrition and oxygen across the body. These are essential for basic metabolism. Metabolic waste including carbon dioxide is removed from these parts of the body through the blood as well. Blood is also used to transport hormones from the site of production to the organs that require the hormones for their normal functions. This makes the blood a useful tool for medical diagnosis as well. The basic health of an individual can be understood by analyzing his or her blood. This is because the blood carries so many important components that are used in the body. By simply measuring these components, one could keep a check on the health of an individual. There are typical values for each of these components.

A complete blood count is a test that measures all the important components in the blood. These components include the quantities of red blood cells, white blood cells and hemoglobin among others. A complete blood count with white cell differential is a slightly more advanced test. This not only measures the components of the blood, it also measures which type of white blood cells are present. There are five different types of white blood cells that are measured in the white blood cell differential. These are basophils, neutrophils, eosinophils, lymphocytes and monocytes. The levels of all these components are important for various different conditions that a patient may be suffering from.

A complete blood count is a common test that may be conducted on a person as part of a general health checkup or for any condition that a patient is hospitalized for. A complete blood count is even used during injuries when an injured person is admitted to an emergency room. This makes it one of the most commonly conducted tests in human medicine. The test is conducted by collecting blood from an individual by using a needle and a vial on the patient’s upper forearm. Blood collection takes just a few seconds and causes little or no discomfort. A patient who is having the test conducted in a clinic may return to his or her normal life immediately without any restrictions. The test results are used to make a preliminary diagnosis of the patient’s condition, following which further tests may be ordered.