A CMP blood test, or comprehensive metabolic panel, checks a patient's blood glucose level, kidney and liver functions, and level of electrolytes, according to WebMD. This test may be included in a yearly physical exam, or it may be used to monitor existing medical conditions.
A CMP also checks the level of calcium in the blood, which is a mineral needed for heart, muscle and nerve functions, according to Lab Tests Online. Total protein and albumin are also measured on a CMP test. Liver functions checked by a CMP include bilirubin, ALT, AST and alkaline phosphatase.
Patients who are scheduled to have a CMP need to fast for 10 to 12 hours prior to the test for accurate results, according to Lab Tests Online.