Blood Test: Comprehensive Metabolic Panel

What Is a Blood Test?

A blood test is when a sample of blood is taken from the body to be tested in a lab. Doctors order blood tests to check things such as the levels of glucose, hemoglobin, or white blood cells. This can help them detect problems like a disease or medical condition. Sometimes, blood tests can help them see how well an organ (such as the liver or kidneys) is working.

What Is a Comprehensive Metabolic Panel (CMP)?

The comprehensive metabolic panel (CMP) is a blood test that gives doctors information about the body's fluid balance, levels of electrolytes like sodium and potassium, and how well the kidneys and liver are working.

Why Are Comprehensive Metabolic Panels Done?

A CMP is done to learn information about the levels of:

• Glucose, a type of sugar used by the body for energy. High glucose levels may point to diabetes.
• Electrolytes:
  • Calcium, which plays an important role in how muscles and nerves work.
  • Sodium, potassium, carbon dioxide, and chloride, which help control the body's fluid levels and its acid-base balance. Normal levels of these electrolytes help keep cells in the body working as they should.
• Blood urea nitrogen (BUN) and creatinine, which are waste products filtered out of the blood by the kidneys. These levels show how well the kidneys are working.
• Albumin and total protein, which are needed to build and maintain muscles, bones, blood, and organ tissue. Low levels may be seen with liver or kidney disease, or nutritional problems.
• Liver tests: Alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin. When these levels are high, it can be a sign of a problem with the liver.

How Should I Prepare for a CMP?

You may be asked to stop eating and drinking for 8–12 hours before a CMP. Tell your doctor about any medicines you take because some drugs might affect the test results. Wearing a T-shirt or short-sleeved shirt can make things easier for you on the day of the test.

What if I Have Questions?

If you have questions about the CMP or what the test results mean, talk to your doctor.