What is a Comprehensive Metabolic Panel (CMP)?

Are you considering taking a Comprehensive Metabolic Panel (CMP-14) with eGFR test?  In this article, we have to break down what this blood panel is all about, common questions, and the specifics of what the test will reveal.  

What Is a CMP-14 Test?  

The Comprehensive Metabolic Panel or CMP blood test is used as an initial broad-spectrum medical tool to check for conditions related to kidney profile, liver panel, and fluids and electrolytes. The CMP, (also known as a metabolic panel, metabolic profile, or complete metabolic panel), is a series of blood tests that provide a snapshot of your body’s chemistry and the way it utilizes energy. It comprises 14 laboratory tests, which will be discussed in this article.

The CMP-14 test will provide you with the following information.  

  • Blood glucose level
  • Protein levels found in your blood
  • Electrolyte levels
  • Kidney and liver levels

Many doctors order this test as part of a general yearly checkup, screen you for potential health problems, and rule out that any medications you might be taking that could be damaging your liver or kidneys.  

Hey, what is eGFR?

Estimated Glomerular Filtration Rate (eGFR) measures the level of kidney function and determines the stage of kidney disease. Estimated Glomerular Filtration Rate (eGFR) is calculated from the blood creatinine test, a person’s age, size, and gender. This test tells the stage of kidney disease and helps the physician plan for the treatment. This test may not be as accurate for people younger than 18 years of age and pregnant women. 

Glomerular filtration rate (GFR) is a measure of kidneys functionality. Glomerulus are tiny filters located in the kidneys that help remove waste products from the blood, while preventing the loss of important constituents, including proteins and blood cells. Glomerulus filters about 200 quarts of blood daily and produces about 2 quarts of urine. The GFR refers to the amount of blood being filtered by the glomeruli per minute. Measuring the GFR directly is complicated, and is typically performed only in research settings and transplant centers. Due to this, the estimated GFR (eGFR) is usually used.

Different equations are used to calculate eGFR. The following are most common: 

  1. Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation (2009)—recommended by the National Kidney Foundation for calculating eGFR in adults
  2. Modification of Diet in Renal Disease Study (MDRD) equation—some laboratories continue to use this equation

Why get tested?

For many, CMP is part of their annual checkup, as this test determines the general health status of a person. But it is mostly used by doctors to screen health problems such as kidney issues, liver problems, hypertension, and diabetes; keep track of chronic medications, or to make sure that medications are not having negative implications on liver or kidneys functions. 

When to get tested?

This test can be ordered through a routine health exam, as suggested by your doctors, when you are ill, being monitored for specific conditions, or experiencing side effects from certain medications. Abnormal results, especially when combined, can indicate a problem that needs to be addressed.

How to prepare for a Comprehensive Metabolic Panel (CMP)?

CMP panel is done by drawing a blood sample from a vein. The preparation varies depending on the reason for testing. Fasting may be needed for at least 12 hours prior to the test.  Other specific instructions might be given to you by the healthcare practitioner.

What is actually being tested in the CMP-14 Panel?

CMP specifically measures the blood levels of the following: panel measures the blood levels of blood urea nitrogen or BUN, creatinine, albumin, calcium, carbon dioxide (Bicarbonate), chloride, glucose, potassium, sodium, total bilirubin, total protein, and liver enzymes (alanine aminotransferase, alkaline phosphatase, and aspartate aminotransferase).

Kidney Profile

Blood Urea Nitrogen (BUN)

Blood Urea Nitrogen or BUN is a by-product of protein metabolism eliminated through the kidneys and an indicator of kidney function. The CMP blood work measures the amount of nitrogen in blood from the waste product, urea. Urea is made in the liver and passed out the body in the form of urine. 


Creatinine is formed when food is changed into energy through a process called metabolism. It is another waste product found in blood and urine. It also is an indicator of how well the kidneys are working. If the kidneys are not working as they should. The amount of creatinine in urine goes down, whereas the level in your blood goes up. The metabolic panel can also test this. 

Blood urea nitrogen to creatinine ratio (BUN:creatinine)

Blood urea nitrogen (BUN) and creatinine tests are used to find the BUN-to-creatinine ratio by dividing the BUN by the creatinine. This ratio can help physicians check for issues that may cause abnormal BUN and creatinine levels. 

Liver panel

Total Serum Protein

Total serum protein measures the total amount of protein in the blood. CMP blood work also measures the amounts of two major groups of proteins in the blood: Albumin and Globulin.

Albumin is a protein made mainly in the liver. It helps keep the blood from leaking out of blood vessels, helps carry some medicines and other substances through the blood, and is vital for tissue growth and healing.

Globulin, on the other hand, is made up of different alpha, beta, and gamma type proteins. Some globulins are made by the liver, while the immune system makes others. Certain globulins bind with hemoglobin. Other globulins transport metals, such as iron, in the blood and help fight infection. Serum globulin can be separated into several subgroups by serum protein electrophoresis. 

Albumin/Globulin Ratio is also tested in the comprehensive metabolic panel. This is calculated by dividing the albumin by the globulin. Albumin/Globulin Ratio can provide further data to determine the status or help diagnose certain liver and kidney disorders and other diseases. 

Fluids & Electrolytes

Electrolytes are minerals found in body tissues and blood in the form of dissolved salts. They help in moving nutrients into the body’s cells and in removing wastes out of the cells.


CMP blood work checks the level of calcium in the body that is not stored in the bones. Almost all of the calcium in the body resides in the bone. Calcium helps the body build and fix bones and teeth, helps nerves work, and helps the heart work properly. 

Carbon Dioxide (Bicarbonate)

The bicarbonate level in a sample of blood from a vein can also be tested using the metabolic panel. Bicarbonate is a chemical that keeps the pH of blood from becoming too acidic or too basic. It helps detect, evaluate, and monitor electrolyte imbalances.


Chloride helps in maintaining the body’s electrolytes in balance. Tests for sodium, potassium, and bicarbonate are usually done at the same time to test chloride.


Sodium is one of the major salts found in the body fluid, and it keeps the body’s water balance and electrical activity. 


Glucose is a type of sugar. It is the body’s primary source of energy. Normally, the blood glucose levels increase slightly after eating, but blood glucose levels that remain high over time can damage your eyes, kidneys, nerves, and blood vessels.


Potassium is both an electrolyte and a mineral. It is essential as it helps control the nerves and muscles. 

What do the results mean?

Like all other tests, the CMP test’s metabolic profile is interpreted within the context of a reference range, other medical testing, and your medical history. A single result slightly higher or lower than the reference range might not have much medical significance. If the Comprehensive Metabolic Panel (CMP) test results are within the range, the results are normal. If they are above or below the range provided, these are considered abnormal results. 

Factors such as biological variability and individual variability may also affect the results. 

  • Biological variability: Due to biological reasons, values may vary from day to day, and sometimes different results may come from the same person if the blood draw is taken at different times. There is a good chance that one result will fall outside a reference range, even if the person is in good health. 
  • Individual variability: A person may be healthy, but the test results do not fall within the reference range. This is because reference ranges are usually established by collecting results from a certain population. From that data, an expected average (mean) result and the expected standard deviation is derived. Not all of the overall population falls within the range. This is generally the case when the test value is only slightly lower or higher than the specified range. 

What are normal results?

Reference ranges could vary depending on the lab that processes the tests.  Labs have special equipment that analyzes your blood, so some results may vary slightly depending on what lab-processed your sample.   We have listed below general ranges for what’s considered normal, but you should always check with your doctor for a specific interpretation of your readings. 

Kidney Tests

  • BUN  (blood urea nitrogen): 6 to 20 mg/dL
  • Creatinine: 0.6 to 1.3 mg/dL

Liver Tests

  • ALP (alkaline phosphatase) : 44 to 147 international units per liter (IU/L)
  • ALT (alanine amino transferase) : 7 to 40 IU/L
  • AST (aspartate amino transferase) : 10 to 34 IU/L
  • Bilirubin: 0.3 to 1.9 milligrams per deciliter (mg/dL)


  • Albumin: 3.4 to 5.4 grams per deciliter (g/dL)
  • Total protein: 6.0 to 8.3 g/dL


  • Sodium: 136 to 145 meq/L
  • Potassium: 3.5 to 5.1 meq/L
  • Chloride : 96 to 106 meq/L
  • CO2 (carbon dioxide): 23 to 29 milliequivalents per liter (meq/L)

Results of the CMP panel are usually evaluated together to look for patterns. A single abnormal test may mean something different. A variety of things may affect a CMP result, such as medications taken (steroids, insulin, hormonal pills), eating or drinking before the test, exercising before the test, and blood cells damaged during the blood test. 

If several of the tests are abnormal, this may also mean something different. For example, a high result on just one of the liver enzyme tests has different implications than high results on several of them. While the individual tests are sensitive, it does not specifically tell what is wrong. The doctor may need to order a follow-up test to make sure. 

The CMP-14 with eGFR blood test is an extensive test and can provide a general status of a person’s health and metabolism. For further information regarding the preparation for the testing and other specific testing details, please refer to our Comprehensive Metabolic Panel (CMP-14) with EGFR Blood Test information page.