The comprehensive metabolic panel (CMP) blood test is group of 14 blood tests that evaluate organ function. Physicians often order the CMP blood test as part of an annual physical, or your doctor may order the test to investigate an existing complaint or symptom. The CMP screens for organ dysfunction by measuring glucose, calcium, pre-albumin, albumin, electrolytes (sodium, CO2, potassium and chloride), blood urea nitrogen (BUN), creatinine, alkaline phosphatase (ALP), alanine amino transferase (ALT), aspartate amino transferase (AST), and bilirubin. Although interpreting the 14 blood tests in the CMP is complicated and requires medical training, a brief description of the tests is presented here.
Electrolytes, including sodium, potassium, carbon dioxide and chlorine, regulate your body’s salt and water balance, and acid-base balance. Electrolytes also are involved with heart rhythm, muscle contraction and nerve conduction. Problems can occur when the level of any electrolyte becomes too high or too low. Dehydration, heart disease, kidney disease, vomiting, dehydration and some medications can alter your electrolyte balance.
BUN and creatinine levels help determine how well your kidneys filter waste from your blood, and high levels of BUN and creatinine point to kidney disease. Decreased blood flow to your kidneys causes a high BUN-creatinine ratio, which occurs with congestive heart failure, increased protein, dehydration and gastrointestinal bleeding. Malnutrition and decreased urea levels, caused by abnormal liver function, are associated with a low BUN-creatinine ratio.
ALT, ALP and AST are liver enzymes, and bilirubin is a byproduct of red blood cell hemolysis in the liver. Abnormal levels of ALT, ALP, AST and bilirubin indicate liver damage or disease. Very high ALT or AST levels indicate acute hepatitis, and a very high ALP level points to bile duct blockage, liver cancer or bone cancer. High bilirubin is associated with jaundice, hemolysis, bile duct blockage, cirrhosis and acute hepatitis. Combinations of these liver function tests can identify the specific disease present.
Low albumin and pre-albumin are associated with kidney disease, liver disease, malnutrition, gastrointestinal protein loss, diarrhea, fever, infection, burns, trauma, obesity, edema and hypocalcemia. Because pre-albumin changes more rapidly, the pre-albumin level is more helpful than the albumin level in detecting rapid changes in nutritional status.
Glucose is the body’s main source of energy, and high glucose levels are primarily associated with diabetes. On the other hand, low blood glucose levels indicate hypoglycemia. Blood glucose also can be high due to liver disease, stress, steroids and pancreatitis. Liver disease, hypothyroidism or alcoholism may lead to low blood glucose.
Calcium is the body’s most abundant mineral, and it is important for muscle contraction, nerve impulses, blood clotting and hormone action. An abnormal calcium level can indicate disorders in your pancreas, kidneys or bones.