The comprehensive metabolic panel, or chemical screen, (CMP; CPT code 80053) is a panel of 14 blood tests which serves as an initial broad screening tool for physicians, nurse practitioners and physician assistants. Because it is often ordered as a routine part of an annual physical examination or check up, over time the CMP provides an important baseline of a patient's basic physiology. Any changes or abnormal results, and in particular combinations of abnormal results, thus provides important initial data for differential diagnosis, in which case more specialized tests may be indicated...