A comprehensive metabolic panel, or CMP, is a blood test that is often ordered by physicians as part of a routine physical exam. The blood test is used to assess liver and kidney functions and to help diagnose medical conditions such as diabetes or hypertension.
This test is also used to monitor patients who take medications that may cause side effects related to liver or kidney function. Medications that may require regular testing include, but are not limited to, diuretics, medications for diabetes and hypertension.
Fasting for 10 to 12 hours may be required before collection of the blood sample for a CMP blood test.
Components of the CMP Blood Test
The comprehensive metabolic panel measures the blood levels of electrolytes, test kidney and liver function, and glucose levels.
Electrolyte imbalance can lead to a variety of symptoms, including nausea, dizziness, muscle cramps, irregular heartbeat or even death. Though sodium and potassium may be tested independently, carbon dioxide and chloride are rarely tested on their own. The electrolytes tested in a CMP blood test include:
Carbon dioxide: may help determine the cause of many symptoms relating to breathing problems.
Chloride: tests for kidney or adrenal gland problems.
Potassium: checks the level of this electrolyte and mineral.
Sodium: checks the level of this electrolyte and mineral.
Concentrated levels of waste products in the blood may indicate a decrease in kidney function, which may be temporary or permanent. Kidney tests are performed to check for increased amounts of these waste products:
Creatinine: tests for kidney problems.
Blood urea nitrogen (BUN): tests for kidney problems.
Tests included in the CMP for liver dysfunction include:
Bilirubin: tests liver function and checks for signs of liver disease.
Liver Enzymes: Alanine aminotransferase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) are liver enzymes. Liver enzyme levels are tested to check for liver disease or damage.
The CMP tests for increased or decreased protein levels with the following tests:
Albumin: tests for liver disorder and kidney disease.
Total Protein: tests for liver and kidney disorders.
Additional tests included in the comprehensive metabolic panel are:
Calcium: tests for problems with the parathyroid glands and kidneys.
Glucose: also known as blood sugar, tests for hyperglycemia, which is too much blood sugar and hypoglycemia, which is too little blood sugar. Glucose levels can alert the physician to the onset and monitors the progress of diabetes.
Results of the CMP Blood Test
The results from the CMP can alert your doctor to potential problems that may or may not be showing symptoms. Although the results of a CMP will not generally tell the doctor what is wrong; elevated or decreased levels may prompt the physician to order additional testing.
Normal ranges vary depending on the age, gender and test method.