What Is a Comprehensive Metabolic Panel (CMP)?

A comprehensive metabolic panel (CMP) is a set of 14 blood tests. It gives your healthcare provider valuable information about your body's metabolism, which is how your body turns food into energy.

The test gives information about your liver and kidney functioning, fluid balance, and electrolyte levels. It may be done to assess your general health or to diagnose and follow the course of certain diseases and their management.

Also referred to as a metabolic panel, chemistry panel, or chem 14, this is a relatively common test that is done from a single blood draw.

This article discusses the purpose of the CMP test, what it tests for, and what you can expect during the test.

Purpose of CMP Test

A CMP helps determine the health of your liver and kidneys and checks the status of your blood sugar and protein levels. It also provides information about your body's electrolytes and fluid balance.

A CMP is typically done as part of your yearly checkup. It can also be ordered if you are ill and hospitalized.

Your healthcare provider may order a comprehensive metabolic panel based on your risk factors for certain conditions, or to monitor them if you're already diagnosed. These conditions include:

• Type 2 diabetes
• Kidney disease
• Liver disease
• Hypertension
  

The CMP doesn't necessarily diagnose a single condition. Given the breadth of the test, it often gives your healthcare provider a starting point to order more targeted tests to diagnose a specific condition.

The test may also be used to monitor medications that could affect kidney or liver function. These drugs may include:

• Pain relievers (acetaminophen, naproxen, ibuprofen)
• Statins
• Antibiotics
• Illicit drugs (cocaine, heroin, amphetamines)

CMP Components

There are 14 tests that make up a comprehensive metabolic panel. These measures are useful to review together, rather than alone, as patterns of results can be more telling—which is why they are tested at the same time. A CMP test shows the following measurements.

Proteins

• Albumin: A protein produced by the liver that helps transport vitamins and enzymes through your bloodstream. The test measures liver function.
• Total protein: Measures all the proteins in the blood

Electrolytes

• Sodium: Essential to basic, normal body function, including fluid maintenance as well as muscle and nerve function. Elevated sodium levels may increase fluid retention and blood pressure.
• Potassium: Helps to maintain proper heart and muscle function. High or low potassium can be related to hypertension and kidney disease.
• Carbon dioxide: Helps maintain your body's pH (acid/base) balance
• Chloride: Affects fluid and pH balance

Kidney Tests

• BUN (blood urea nitrogen): The kidneys remove this waste product from the blood. High levels are a red flag for kidney function. A BUN that's low may occur with pregnancy, in people with liver failure, and in those overly hydrated.
• Creatinine: A waste product created by muscle function. Elevated levels could indicate kidney problems. Low levels may indicate malnutrition or severe liver disease.

Liver Tests

• ALP (alkaline phosphatase): A liver and bone enzyme that can indicate liver damage and bone disorders
• ALT (alanine aminotransferase): A liver and kidney enzyme
• (aspartate aminotransferase) AST: A heart and liver enzyme
• Bilirubin: A liver waste product

Other

• Glucose: Also referred to as your blood sugar, this is your body's main source of energy. Elevated blood sugar can be a sign of prediabetes and diabetes.
• Calcium: This mineral is critical for proper muscle and heart function, as well as bone formation.

Before the CMP Test

A complete metabolic panel takes only a few minutes. It may be done at your healthcare provider's office or lab facility. It may also be done in an ER setting or if you've been admitted to the hospital.

The test may require fasting for a minimum of eight hours, so many people schedule it for first thing in the morning so they can eat when it's done.

The blood draw will be taken from your arm, so it makes sense to wear something with sleeves that can be easily rolled up.

During the CMP Test

A metabolic panel is based on a single blood draw.

The procedure followed is the same as with any other venipuncture, and your sample will be collected by a nurse or phlebotomist.

1. The draw site will be cleaned with alcohol.
2. A tourniquet will be placed above the area where the needle will be inserted. You may also be asked to squeeze something to draw more blood into your vein.
3. A small needle will be inserted so blood can be collected.
4. Once the vial is full, the needle will be taken out, pressure will be put on the site, and a bandage will be placed.

You will be allowed to leave right after the test. Your sample will then be sent to a lab for analysis.

Risks

A comprehensive metabolic panel is generally safe. The only risks stem from the blood draw itself, and these tend to resolve quickly. You may experience:

• Bruising/bleeding at the injection site
• Soreness from multiple sticks to find a vein
• Infection
• Anxiety and/or dizziness from having blood taken

Interpreting CMP Results

Your healthcare provider should get results back quickly, in a day or two at the most. They are presented with normal ranges as well as your individual levels. The "normal" range may vary by lab, because each lab sets its one "normal" reference range.

This gives healthcare providers a comprehensive look at overall metabolic health, particularly the liver and kidneys and their different processes.

Your healthcare provider will typically look for patterns in various results rather than at one specific result. Mildly higher or lower results in one area may not be medically significant.

In the case of someone hospitalized, multiple CMPs may be ordered on different days to monitor progress.

Follow-Up

While abnormal tests could indicate serious medical conditions like diabetes and kidney/liver problems, more condition-specific tests will follow to achieve an accurate diagnosis.

If your healthcare provider wants to perform an even deeper metabolic workup, the following additional blood tests can be ordered (if they haven't been already):

• Complete blood cell count (CBC)
• Thyroid tests
• Creatine phosphokinase (CPK)
• Vitamin B12 level
• Ammonia (ammonium ion test)
• Hemoglobin A1C

A Word From Verywell

Be sure to have a thorough discussion with your healthcare provider about any abnormal results and what further steps you may have to take to address concerns. The best way to reduce any test anxiety is by asking questions and having a full understanding of what a CMP means for your health.