This article talks about what a CMP test is, the different components of the CMP test, and what your results may mean.
A CMP test provides important information about your body’s chemical and electrolyte balance and metabolism. Metabolism is how your body processes food and energy.
The liver and kidneys play key roles in metabolism. The CMP test measures how well these organs are working. The CMP test measures 14 different substances. They are:
- Alanine aminotransferase (ALT): This liver enzyme may indicate that the liver is damaged or diseased.
- Albumin: This protein is mostly made in the liver. It helps keep the blood from leaking out of the blood vessels.
- Alkaline phosphatase (ALP): This enzyme is made mostly in the liver, bone, and placenta of pregnant people.
- Aspartate aminotransferase (AST): This enzyme is present in the liver, red blood cells, heart, muscle tissue, pancreas, and kidneys.
- Blood urea nitrogen (BUN): This measures the amount of nitrogen in your blood that comes from the waste product urea and tests to see how well your kidneys are working.
- Calcium: This is one of your body’s most important minerals, and it is essential for the proper functioning of your nerves, muscles, and heart.
- Carbon dioxide: This gaseous waste product acts as a buffer and keeps the pH of the blood from becoming too acidic or too basic.
- Chloride: This electrolyte helps maintain blood volume, blood pressure, and pH of your body fluids.
- Creatinine: The CMP test checks how well your kidneys are working by measuring the amount of creatinine, which is a waste product in your blood.
- Glucose: This is a type of sugar and your body’s main source of energy.
- Sodium: This electrolyte helps keep the body’s balance of water and electrolytes in check. It also plays a role in how nerves and muscles work.
- Potassium: This electrolyte and mineral also keeps the body’s balance of water and electrolytes in check and plays a role in how nerves and muscles work.
- Total protein: The CMP test measures two major groups of proteins in the blood: albumin and globulin. Both groups of proteins are made in the liver.
- Total bilirubin: This brownish yellow substance present in bile is produced when the liver breaks down old red blood cells.
Doctors may request a CMP test as part of a routine annual checkup. The test is also used to monitor for certain conditions, such as in the liver or kidneys. A CMP test can also help monitor for side effects of certain medications.
Your doctor may check a CMP in addition to other tests such as a complete blood count.
A CMP test can be used to check several body functions, such as:
- metabolism
- acid and base balance
- fluid and electrolyte balance
- blood sugar levels
- blood protein levels
- liver and kidney health
If you have chronic liver or kidney disease, your doctor will want to check your CMP regularly.
Expected ranges for each test depend on factors such as sex, age, and test method. Ranges can also vary slightly based on the laboratory performing the tests. The laboratory test results report will show the expected normal ranges for each test performed by the specific laboratory.
Your doctor will be familiar with the expected laboratory test ranges for the laboratory they use. They will discuss your results with you based on your health history, the medications you take, and your reason for having the test. When results are not within the expected range, your doctor may repeat the test to confirm the result or order additional testing.
If one or more of the components of the CMP test is not within the expected range, it may indicate a possible medical condition or even a laboratory error. Each test of the CMP may indicate different disease processes depending on a high or low level.
Provide a complete list of medications you take to your doctor. Medications can interfere with any component of the CMP test and result in either high or low results.
Here is an overview of the generally expected ranges for the different components of the CMP test and what it may mean if the result is high or low. The ranges noted here are for adults, and they may vary slightly for children. Remember, your test results report will list the expected normal ranges for each test for that individual laboratory.
A CMP test involves a simple blood draw and typically takes 5 minutes. No special preparation is needed. If you are having additional tests done, your doctor may ask you to fast (not eat or drink) for 8 hours before the test. You can expect test results within 24–48 hours.
Typically, if your doctor determines that you need three or more of the tests in the CMP, it is often more cost effective to have a CMP test than to have individual tests.
The expected range of ALT is 10–40 units per liter (u/l).
When your results are high, it may be due to:
- cirrhosis
- hepatitis
- liver infection
- liver cancer
Low levels of ALT are usually not a cause for concern. However, some studies suggest that low ALT in certain populations is associated with increased long-term mortality.
The expected range for albumin is 3.5–5.5 grams per deciliter (g/dl).
Severe dehydration can cause high levels of albumin.
Causes of low levels of albumin include:
- autoimmune diseases
- heart failure
- Hodgkin lymphoma
- hyperthyroidism
- liver or kidney disease
- malabsorption syndromes
- malnutrition
- uncontrolled diabetes
The expected range for ALP is 20–130 u/l. Ranges may be much higher for children and adolescents.
Causes of high levels of ALP include:
- bile duct blockage
- cirrhosis
- heart failure
- hepatitis
- mononucleosis
- several medications
Causes of low levels of ALP include:
- inherited bone diseases
- malnutrition
- zinc deficiency
The expected range of AST is 10–40 u/l.
Causes of high levels of AST include:
- liver damage
- heart attack or heart failure
- mononucleosis
- pancreatitis
Low levels of AST are typical and usually not a cause for concern.
The expected range of BUN is 8–20 milligrams per deciliter (mg/dl).
Causes of high BUN levels can indicate:
- Addison’s disease
- dehydration
- gastrointestinal bleeding
- heart failure
- a high protein diet
- kidney damage
- severe burns
- several medications
Low BUN levels can indicate:
- cirrhosis
- drinking too much water
- liver damage
- malnutrition or a diet low in protein
- pregnancy
- rhabdomyolysis
- syndrome of inappropriate antidiuretic hormone secretion
The expected range for calcium is 8.6–10.2 mg/dl.
High levels of calcium can indicate:
- a broken bone with prolonged bed rest
- cancer, such as cancer that has spread to the bone
- hyperparathyroidism
- Paget’s disease
- tuberculosis
Low levels of calcium can indicate:
- high phosphate levels in the blood
- hypoparathyroidism
- low levels of vitamin D and magnesium
- malnutrition, or little calcium in your diet
- osteomalacia
- rickets
The expected range for carbon dioxide is 23–30 milliequivalents per liter (meq/l).
Causes of high levels of carbon dioxide include:
- chronic obstructive pulmonary disease (COPD)
- Conn’s syndrome
- Cushing’s disease
- dehydration
- heart disease
- pulmonary edema
- overuse of antacids or other medications containing bicarbonate
- vomiting
Low levels of carbon dioxide may be due to:
- excessive aspirin or alcohol use
- diarrhea, dehydration, or malnutrition
- heart attack
- hyperthyroidism
- hyperventilation
- liver or kidney disease
- sepsis
- uncontrolled diabetes
The expected range of chloride is 98–106 meq/l.
Causes of high chloride levels include:
- consuming too much salt
- dehydration
- hyperparathyroidism
- kidney disease
- metabolic acidosis
Causes of low levels of chloride include:
- heart failure
- Addison’s disease
- metabolic alkalosis
- severe vomiting
The expected ranges are 0.5–1.1 mg/dl in females and 0.7–1.3 mg/dl in males.
Causes of high creatinine levels include:
- dehydration
- muscle injuries
- strenuous exercise
- severe kidney damage or chronic kidney disease
- shock
Low creatinine levels can indicate:
- a diet low in protein
- lower muscle mass caused by aging
- muscular dystrophy
- severe liver disease
The expected range of glucose is 70–99 mg/dl. High glucose values can indicate diabetes. Your doctor will use certain criteria to evaluate whether or not you have diabetes based on your glucose level.
Other conditions that can cause high glucose levels include:
- certain medications, such as corticosteroids
- heart attack
- hyperthyroidism
- pancreas disorders
- severe stress
- stroke
Causes of low glucose levels include:
- Addison’s disease
- diabetes medications
- hypothyroidism
- kidney disease
- liver disease, such as cirrhosis
- malnutrition or eating disorders
- pituitary gland tumors
The expected potassium range is 3.5–5.0 meq/l.
High levels of potassium can mean:
- diabetic ketoacidosisis
- kidney damage
- severe burns
- heart attack
Low levels of potassium can mean:
- alcohol use disorder
- cystic fibrosis
- diarrhea, dehydration, or malnutrition
- hyperaldosteronism
- severe vomiting
The expected range for sodium is 136–145 meq/l.
High levels of sodium can be caused by:
- diabetic ketoacidosis
- dehydration
- a high sodium diet
- hyperaldosteronism
- kidney disease
- certain medications, such as diuretics
- severe vomiting or diarrhea
Causes of low levels of sodium include:
- cirrhosis
- cystic fibrosis
- drinking too much water
- excessive sweating
- heart failure
- kidney disease
- severe vomiting or diarrhea
- poor nutrition
- underactive adrenal or thyroid glands
The expected range for total bilirubin is 0.3–1.0 mg/dl.
High levels of total bilirubin may indicate:
- blood transfusion reaction
- cholecystitis
- gallstones
- liver damage
- pancreatic cancer
- sickle cell disease
- certain medications, such as:
- antibiotics
- certain types of birth control
- diazepam
- flurazepam
- indomethacin
- phenytoin
Some medications — such as vitamin C, phenobarbital, and theophylline — can cause low levels of total bilirubin.
The expected range of total protein is 5.5–9.0 g/dl.
High levels of serum protein can be caused by:
- certain infections, such as HIV or hepatitis
- multiple myeloma, which is a type of blood cancer
Low levels of serum protein may indicate:
- liver or kidney disease
- malnutrition
- malabsorption syndromes, such as celiac disease or Crohn’s disease
Both a CMP and a basic metabolic panel (BMP) assess the body’s metabolism and fluid and electrolyte balance. However, a CMP has more components to the test than a BMP.
The six additional tests in a CMP are:
- ALT
- ALP
- AST
- total protein
- total bilirubin
- albumin
There are few risks associated with getting a CMP test. You may experience a slight pinch when the needle is inserted into your arm and some mild bleeding. If you have excessive bleeding or develop a large bruise where the needle was inserted, let your doctor know right away.
A comprehensive metabolic panel (CMP) measures 14 different substances to assess the body’s kidney and liver function. Doctors will request a CMP test as part of a routine annual checkup or if they are monitoring chronic liver or kidney disease.
There are minimal risks to getting this test. If your results are outside an expected range, your doctor may repeat the test or order additional blood work.
