Understanding the Comprehensive Metabolic Panel Test

A comprehensive metabolic panel (CMP) is a standard blood test that offers a detailed snapshot of your overall health. By measuring a range of substances in your blood, healthcare providers can detect potential issues with your kidneys, liver, blood sugar, and electrolyte balance. 

Whether it’s part of a routine checkup or used to monitor an ongoing condition, understanding your CMP results can give you valuable insights into your health.

What is a CMP Lab Test?

A CMP is a blood test that measures the levels of several substances in the body, including proteins, enzymes, minerals, and electrolytes. It is often performed as part of routine health monitoring and is also known as a chem-14, chemistry screen, or chemistry panel. 

A CMP blood test can help healthcare providers:

• Screen for health conditions in their early stages before any symptoms appear

• Diagnose medical conditions, such as liver and kidney disease

• Monitor health conditions or side effects of medications.

The key information provided by a CMP includes:

• Liver function 

• Kidney function

• Blood sugar level

• Fluid and electrolyte/acid-base balance

What Is Included in a CMP Lab Test?

A CMP measures 14 different substances in a blood sample. These are:

• Alanine transaminase (ALT) 

• Albumin

• Alkaline phosphatase (ALP) 

• Aspartate aminotransferase (AST)

• Bicarbonate/carbon dioxide 

• Bilirubin 

• BUN (blood urea nitrogen) 

• Calcium 

• Chloride 

• Creatinine 

• Glucose

• Potassium 

• Sodium 

• Total protein 

Comprehensive vs. Basic Metabolic Panel

A basic metabolic panel (BMP) is a routine blood test similar to a CMP. The main difference between a CMP and a basic metabolic panel (BMP) is that CMP measures 14 substances while BMP measures eight substances in blood. 

The 8 tests included in a basic metabolic panel include:

• Bicarbonate

• Blood urea nitrogen (BUN)

• Calcium

• Chloride 

• Creatinine

• Glucose

• Potassium

• Sodium

Your healthcare provider may choose a CMP over a BMP if your symptoms suggest a liver condition or if you are being monitored for known liver disease. In addition to all the tests included in a BMP, a CMP also helps your healthcare provider assess liver function by measuring the following substances:

• Liver enzymes, including alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Elevated levels of these enzymes can indicate liver damage or bone conditions.

• Albumin and total protein, which can point towards liver or kidney issues.

• Bilirubin is a waste product that is formed when the liver breaks down old red blood cells.

Both BMP and CMP include the following tests:

• BUN and creatinine levels: These are waste products that the kidneys remove from the blood. High levels in the blood can point towards decreased kidney function.

• Electrolytes: Sodium, potassium, chloride, calcium, and bicarbonate (carbon dioxide) play essential roles in muscle and nerve function, heart function, and maintaining fluid balance and pH balance (acid-base balance) in the body. 

• Glucose: This is the body’s main energy source. High blood sugar (glucose) levels indicate a chronic disease, such as diabetes. 

Test Procedure and Preparation  

The CMP test is performed on a small sample of blood drawn from a vein in your arm. 

Usually, you won't need to fast before a Comprehensive Metabolic Panel (CMP), but it's always a good idea to check with your healthcare provider. 

They can let you know if you should avoid eating or drinking for 10 to 12 hours before your test, especially if it's your first time.    

What To Expect During The Blood Test  

A CMP lab test is performed by a laboratory technician called a phlebotomist. The entire process usually takes 5-15 minutes.

1. You will be seated in a chair.

2. The phlebotomist will look for an easily accessible vein in your arm, typically located in the inner elbow area.

3. They will disinfect your skin with an alcohol swab and draw blood using a thin needle. You may feel a slight pinch when the needle is inserted.

4. The phlebotomist will remove the needle and hold a cotton gauze on the puncture site to stop the bleeding.

5. They will place a small bandage on the blood draw site.

6. The test tube with your blood sample will be sent to the laboratory for CMP testing.

7. There may be slight pain and bruising at the needle prick site, which is temporary. There is minimal risk involved with a CMP test, although the needle prick can put you at a slight risk of infection.

Interpreting Test Results  

Normal CMP values in adults are as follows:

• Alanine transaminase (ALT): 4 to 36 international units per liter (U/L)

• Alkaline phosphatase (ALP): 20 to 130 U/L

• Aspartate aminotransferase (AST): 8 to 33 U/L

• Bilirubin: 0.1 to 1.2 milligrams per deciliter (mg/dL) 

• Albumin: 3.4 to 5.4 grams per deciliter (g/dL)

• Total protein: 6 to 8.3 g/dL

• BUN (blood urea nitrogen): 6 to 20 mg/dL

• Creatinine: 0.6 to 1.3 mg/dL

• Sodium: 135 to 145 milliequivalent per liter (mEq/L)

• Potassium: 3.7 to 5.2 mEq/L

• Calcium: 8.5 to 10.2 mg/dL

• Chloride: 96 to 106 mEq/L

• Bicarbonate/carbon dioxide: 23 to 29 mEq/L

• Glucose: 70 to 100 mg/dL 

CMP test results outside these ranges are considered abnormal levels. 

Keep in mind that for some of the tests, such as creatinine, the normal range can vary with age and muscle mass. 

The normal ranges can also vary slightly among different laboratories. Some laboratories may use different units of measurement. 

Common Health Conditions Detected By Abnormal CMP Results 

Some of the conditions that may be suspected or diagnosed based on CMP results include:

• Liver disease

• Kidney disease

• High blood pressure

• Diabetes, including type 1 and type 2 diabetes mellitus

What Cancers Does CMP Detect?

A CMP does not directly detect cancer. 

It primarily assesses kidney, liver, and metabolic functions. But a CMP can provide information that may indicate the presence of certain types of cancer, especially blood cancers like leukemia, lymphoma, and multiple myeloma. 

Abnormal results, such as elevated total protein on CMP, can point towards the possibility of blood cancers. 

Follow-Up With A Healthcare Provider  

A comprehensive metabolic panel is a routine test that provides a lot of information about your body. It’s important to follow up with a healthcare professional to understand your comprehensive metabolic panel results. Your provider will take into account your health history, general symptom complaints, and medications (including prescription, over-the-counter, and illegal drugs, if any) to interpret the results correctly. They may order additional tests to assess liver and kidney health and rule out or diagnose certain conditions.

CMP Testing Costs 

How Much Does A CMP Blood Test Cost?  

The cost of a comprehensive metabolic panel (CMP) can vary, depending on factors such as the location of the lab, insurance coverage, and whether the test is performed in an outpatient clinic or hospital setting. 

CMP Cost With Insurance

Many health insurance plans cover the cost of a CMP as part of preventive care during a routine checkup. The test is also usually covered when done for diagnostic testing. 

The out-of-pocket cost of a CMP test depends on the terms of your insurance plan. You should contact your insurance provider or healthcare provider to find out whether CMP is covered by your health plan and the cost. 

CMP Cost Without Insurance

The average cost of a comprehensive metabolic panel (CMP) without insurance ranges from $60 to $80. Laboratories such as Labcorp OnDemand and Quest Diagnostics offer this panel of tests for a low price of $49.

Related Diagnostic Tests  

Complete Blood Count (CBC) 

A complete blood count (CBC) measures the quantity of various types of blood cells, including white blood cells, red blood cells, and platelets. It is done to assess overall health and can diagnose medical conditions such as anemia, infections, and blood cancers like leukemia.

A comprehensive metabolic panel (CMP) measures various substances that help healthcare providers assess metabolic health and evaluate organ function, including liver and kidney health.

Additional Tests 

Based on CMP test results, your health care professional may recommend more tests such as:

• Liver enzymes such as gamma-glutamyl transpeptidase (GGT)

• The estimated glomerular filtration rate (eGFR), which measures how well the kidneys filter blood

• Prealbumin

• Urine tests

• Hemoglobin, serum iron level, ferritin, transferrin, and complete blood count (CBC) to evaluate for anemia and blood disorders.

What Is an Anion Gap POC?

The difference between positively charged electrolytes (sodium, potassium, calcium) and negatively charged electrolytes (chloride, bicarbonate) is called an anion gap POC (point-of-care) test. Healthcare providers can use CMP results to calculate the anion gap.