Comprehensive Metabolic Panel (CMP): An Overview

Medically Reviewed by Zilpah Sheikh, MD on January 11, 2024
9 min read

A comprehensive metabolic panel (CMP) is a series of 14 blood tests. It gives your doctor a snapshot of how your liver and kidneys are working, your blood sugar (glucose) level, and your electrolyte and fluid balance.

The 14 tests include alkaline phosphatase(ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, blood urea nitrogen (BUN), creatinine, sodium, potassium, carbon dioxide, chloride, albumin, total protein, glucose, and calcium.

It’s also called a metabolic panel, chem 14, chemistry panel, or chemistry screen.

Comprehensive metabolic panel vs. basic metabolic panel

The doctor may test you with a basic metabolic panel (BMP) instead of a CMP based on your health history and your needs. A BMP can help your doctor understand how your body is using your food and how the chemicals in your body are balanced. It includes eight of the same tests as a CMP: BUN, creatinine, carbon dioxide, chloride, potassium, sodium, glucose, and calcium. Your doctor may order this instead of a CMP:

  • As part of your regular checkup
  • When you go to the ER
  • When you have some long-term conditions, such as high blood pressure or kidney disease

It's also called a chem 7 or electrolyte panel.

You may get a CMP as part of your yearly checkup, or you may get it to check for kidney or liver diseases. The doctor might also want one to check you for any medical problems, keep track of any chronic conditions you have, or make sure certain medications aren’t hurting your liver or kidneys.

The CMP can tell your doctor:

  • How your kidneys and liver are working
  • How much protein is in your blood 
  • Your electrolyte levels
  • The balance of acid and base in your blood
  • Your blood sugar levels

Most labs do the same tests, but this may vary slightly depending on the lab or what your doctor has asked them to test.

Most CMPs include the following 14 tests:

CMP liver and protein tests

Albumin. It's made in your liver and is the main protein in your blood and carries hormones, vitamins, and enzymes throughout your body. Low levels may be a sign of liver or kidney disease or another medical condition. High levels may be a sign of dehydration.

Alkaline phosphatase (ALP). It's a protein made in your liver, bones, kidneys, and digestive system. Abnormal levels of ALP may be a sign of health conditions, such as liver disease, bone disorders, and chronic kidney disease.

Alanine aminotransferase (ALT). It's a protein made mostly in the liver. Damaged liver cells release ALT into your blood. High levels in your blood may be a sign of liver injury or disease. You may have high ALT levels in your blood before you have any symptoms, so an ALT test can give your doctor a way of catching some liver diseases early.

Aspartate aminotransferase (AST). This protein is made mostly in your liver, but also in some muscles and other organs. Your doctor may use this test to help diagnose or monitor liver damage or disease.

Total protein. It refers to the total amount of protein in your blood, which includes albumin and globulin. Globulins are proteins that help fight infections and carry nutrients in your body. Some globulins are made in the liver and others are made by the immune system. Low total protein levels can be a sign of a serious health problem.

Bilirubin. It's a yellow chemical your body makes when it breaks down old red blood cells. Your liver usually filters most of the bilirubin out of your blood. If your liver is damaged, bilirubin can leak out. If you have too much bilirubin in your blood, you may get jaundice, when your skin and eyes turn yellow. This test can help your doctor check on how well your liver is working.

CMP kidney tests

Blood urea nitrogen (BUN). Urea nitrogen is a waste product that your kidneys filter out of your blood. High BUN levels may be a sign that your kidneys aren't working well. You may have high BUN levels in your blood before you have any symptoms of kidney disease, so this test can give your doctor a way of catching some kidney problems early. This test may also be called a urea nitrogen test or serum BUN.

Creatinine. It's a normal breakdown product in your body. Your muscles make it when you work them hard. Your kidneys usually filter creatinine out of your blood. High levels of creatinine may be a sign of kidney disease, dehydration, muscle disorders, body injury, muscular dystrophy, or intense exercise. This test may also be called serum creatinine, kidney function, or renal function. The lab often uses this result to calculate an estimated glomerular filtration rate (eGFR) and also compares it to your BUN. These calculations can help your doctor figure out if you have a serious kidney problem and possibly why you're having it.

CMP electrolyte tests

Carbon dioxide (CO2) is a breakdown product your body makes when you digest food. You breathe it out of your lungs when you exhale. Most of the CO2 in your blood is bicarbonate, which is an electrolyte. Electrolytes are electrically charged minerals that help you control the amount of fluid in your body as well as your pH balance (balance of acids and bases). High or low levels can be a sign you have an electrolyte imbalance. Diseases that can cause an electrolyte imbalance include high blood pressure and kidney, lung, or liver conditions.

Chloride is a type of electrolyte, and abnormal levels can be a sign you have an electrolyte imbalance. High levels may be a sign of dehydration, kidney disease, or acidosis (having too much acid in your blood). Low levels may be a sign of heart failure, lung disease, Addison disease (a condition where your adrenal glands don't make enough of certain hormones), or alkalosis (having too much base in your blood). You may also have abnormal levels of chloride if you are overhydrated, dehydrated, or if you've taken antacids.

Potassium isnecessary for your cells, nerves, heart, and muscles to work well. High levels may be a sign of kidney disease, Addison disease, or type 1 diabetes. High levels may also be from injury, burns, surgery, or certain medicines, such as diuretics or antibiotics. Low levels may be a sign of adrenal gland disorders (such as Cushing's syndrome and aldosteronism), kidney disease, or alcohol use disorder. It can also be from diuretics, dehydration, or laxatives.

Sodium is necessary for your nerves and muscles to work well. High levels may be a sign of dehydration, adrenal gland disorders, kidney problems, and diabetes insipidus (a disorder of your kidneys or pituitary gland that makes you very thirsty so that you drink and pee a lot). Low levels may be a sign of dehydration, kidney diseases, cirrhosis of the liver, heart failure, Addison disease, some brain and lung diseases, and some types of cancer. It can also be from over-the-counter pain medicine or antidepressants.

CMP glucose test

Glucose is a type of sugar and your body's main source of energy. High levels may be a sign of diabetes or other disorders of your pancreas, hyperthyroidism, or stress from surgery, trauma, or other serious illnesses. If you have diabetes, low levels may be due to too much diabetes medicine, not eating enough, or exercising more than you usually do. If you don't have diabetes, low levels may be a sign of liver or kidney disease, alcohol use disorder, hypothyroidism, or an underactive adrenal or pituitary gland.

CMP calcium test

Calcium is one of the most important minerals in your body. You need the right amount of calcium in your blood for your nerves, muscles, and heart to work well. Low levels of calcium may be a sign of bone disease, thyroid disease, parathyroid disorders, kidney disease, or other conditions.

A health care professional will use a small needle to take a blood sample from a vein in your arm. They’ll collect the blood in test tubes or vials. You may feel a little sting when they put the needle in or pull it out. The whole process usually takes less than 5 minutes.

Afterward, you may have slight pain or bruising at the spot where the needle went in, but most symptoms go away quickly.

If you’re in the hospital, the doctor may do daily tests. If you aren’t in the hospital, but you have a condition such as diabetes or kidney disease, you may go to the doctor’s office or a clinic every few months for tests.

Who performs a comprehensive metabolic panel?

Any health care professional who is trained in drawing blood can perform a CMP, but it's usually done by a phlebotomist. Phlebotomists are health care professionals who specialize in drawing blood from adults and children. They collect and prepare your blood so it can be tested in a medical lab.

After they draw your blood, they will send it to a lab, where medical lab scientists prepare the samples and use specialized machines to analyze them.

Comprehensive metabolic panel fasting

You will usually need to fast (avoid eating or drinking) before your test. If so, it's usually for at least 8-12 hours. This is so that any food you have eaten won't interfere with your glucose levels. Your doctor will usually let you know if you need to fast and how long you should fast before your test.

Don't exercise before your test because this can affect your results, especially your ALT and AST levels. Also, be ready to tell your doctor about any medicines (including prescription, over-the-counter, and illegal drugs), herbs, vitamins, and supplements you take.

Reference ranges depend on the lab that analyzes your blood tests because different labs use their own equipment. They also have different ways of analyzing your blood.

Your doctor will look at all your test results together to see if there are patterns that suggest a medical condition. They will also consider your health history, any medicines you take, and any other factors that may affect your results. Ask your doctor to help you understand what your results mean.

Normal comprehensive metabolic panel results

General ranges for normal results are as follows:

  • Albumin: 3.4-5.4 grams/deciliter (34 to 54 grams/liter)
  • ALP: 20-130 units/liter
  • ALT: 4-36 units/liter
  • AST: 8-33 units/liter
  • Total protein: 6.0-8.3 grams/deciliter (60 to 83 grams/liter)
  • Bilirubin: 0.1-1.2 milligrams/deciliter (2 to 21 micromoles/liter)
  • BUN: 6-20 milligrams/deciliter (2.14 to 7.14 millimoles/liter)
  • Creatinine: 0.6-1.3 milligrams/deciliter (53 to 114.9 micromoles/liter)
  • CO2 (carbon dioxide): 23-29 milliequivalents/liter (23 to 29 millimoles/liter)
  • Chloride: 96-106 milliequivalents/liter (96 to 106 millimoles/liter)
  • Potassium: 3.7-5.2 milliequivalents/liter (3.70 to 5.20 millimoles/liter)
  • Sodium: 135-145 milliequivalents/liter (135 to 145 millimoles/liter)
  • Glucose: 70-100 milligrams/deciliters (3.9 to 5.6 millimoles/liter)
  • Calcium: 8.5-10.2 milligrams/deciliter (2.13 to 2.55 millimoles/liter) 

But always go by the ranges that are on your report because that’s what your doctor will use.

Abnormal comprehensive metabolic panel results

If any of your results are not what they should be, your doctor might ask you to come back for more tests. This will help your doctor figure out if there’s a true problem.

A lot of things can affect your CMP results, such as:

  • Medications you take, such as steroids, insulin, and hormones
  • Eating or drinking before the test
  • Exercising before the test
  • Blood cell damage that may happen while your blood is collected or when the sample is prepared for analysis

Ask your doctor about any abnormal results because they can help you understand what your results mean.

A comprehensive metabolic panel (CMP) is a test that measures 14 different chemicals in a sample of your blood. It gives your doctor an idea of how well your liver and kidneys are working, how much protein and electrolytes you have, your acid-base balance, and your blood sugar levels. Many people get a CMP during their routine checkup, but your doctor may also use it to keep track of how well your medicines are working or to check for kidney or liver diseases. You usually need to fast for the test, but your doctor will let you know if you do. Abnormal results don't always mean you have a medical condition because lots of things can affect your results. Ask your doctor to go through your results with you so you can understand what your results mean for your body.