The clinical hematology laboratory contains two different types of testing: hematological and coagulation testing. On the hematological side of testing, the main test performed is the complete blood count (CBC), which directly measures the number of red blood cells, white blood cells, platelets, and hemoglobin, as well as indirectly measuring other values by calculations. These tests are performed using a well-mixed whole blood sample that has been collected in a tube containing ethylene diamine triacetic acid, also known as EDTA. Before hematological results are sent out to the healthcare team, they are reviewed by the medical laboratory technologist (MLT). Any abnormal results that are seen by the MLT (either increased or decreased beyond reference ranges) are made into slides and further microscopic analyses are performed. Some results may even be “critical” in the sense that they are so abnormal that the patient may be at risk if the result is not reported immediately. While reviewing parameters, certain “checks” are also performed as an internal quality control system for the sample. One of these kinds of systems include delta checks, which are a comparison of a patient’s previous results to those most current. While changes in values can occur due to the physiological state of the patient, these internal checks are also great for identifying if a sample was taken from the wrong patient.