The comprehensive metabolic panel, or CMP, a common blood test, offers a detailed overview of your metabolic health—how well your body processes food into energy—and how well certain organs are working. The CMP measures levels of key electrolytes along with enzymes and other proteins. Your doctor may use the test to screen you for a variety of medical conditions or monitor the effectiveness of treatment and check on side effects of medications.
The CMP annually gives your doctor the ability to compare recent results to past tests and spot changes early on, when steps can be taken to correct any issues. You might have this test more frequently if you have diabetes or liver disease.
Elena N. Zamora, MD, board-certified family medicine physician and assistant professor at UTHealth Houston, explains what you need to know about your own CMP.
What Is a Comprehensive Metabolic Panel Exactly?
This blood test measures levels of different substances to create a snapshot of your health, including the state of your liver and kidneys. The results can confirm that you’re healthy or indicate a potential problem to investigate. Out-of-range results can be caused by many health conditions, from an infection or malnutrition (which happens to more seniors than you might think) to liver or kidney disease, among many others. The CMP doesn’t measure blood fats, or lipids, so it won’t tell you if you have normal cholesterol—that requires a lipid panel blood test.
Note: Different testing labs use somewhat different ranges, so where your numbers fall in relation to your lab’s normal range may differ from these normal readings.
Glucose
Your glucose level indicates how well your body is processing sugar. What to look for…
Between 70 milligrams/deciliter (mg/dL) to 100 mg/dL is normal.
Between 100 mg/dL and 125 mg/dL indicates prediabetes.
Over 126 mg/dL if fasting or over 200 mg/dL indicates diabetes.
Depending on your results, your doctor may want to follow up with an A1C test, a more precise measure of blood glucose. An A1C range greater than 6.5 mmol/L typically confirms a diabetes diagnosis…an A1C between 5.7 and 6.4 usually confirms prediabetes.
Calcium
Besides building strong bones, calcium is essential for your heart, muscles and nerves. The normal range is 8.5 mg/dL to 10.2 mg/dL. A higher number could indicate that your parathyroid gland is putting out too much parathyroid hormone, which could cause bone thinning, kidney stones, fatigue and muscle weakness. A low number could mean a vitamin D deficiency, causing fatigue, bone pain and muscle weakness. The CMP does not measure calcium levels in bone—for that you need a bone density test.
Electrolytes
Electrolytes are electrically charged minerals that help control the amount of fluid in your body and maintain the right pH level, often called the body’s acid-base balance. They also control muscle and nerve function—low levels of electrolytes can cause muscle weakness, fatigue, nausea and vomiting. These four electrolytes work together and are included in the CMP test…
Sodium
Normal range: 135 milliequivalents per liter (mEq/L) to 145 mEq/L. Sodium levels can be affected not only by the amount of salt you eat but also certain medications—NSAIDs, laxatives and steroids can cause sodium levels to rise, while diuretics and some antidepressants can cause it to be low. High sodium also can be a sign of malnourishment. Some lung infections, such as Legionella, can cause a drop, as can endocrine conditions such as Addison’s disease. Restoring low sodium must be done slowly to avoid swelling, especially in the brain. Depending on the cause of low sodium as well as the sodium level, treatments ranging from fluid restriction to salt tablets and IV fluids with sodium can be used.
Potassium
Normal range: 3.7 mEq/L to 5.2 mEq/L. Dehydration…kidney diseases especially late-stage renal disease…some endocrine disorders…and medications, including ACE inhibitors can cause high potassium. High and low levels of potassium can cause irregular heartbeat and heart rhythm.
Bicarbonate
Normal range: 22 mEq/L to 29 mEq/L. Bicarbonate indicates the amount of carbon dioxide (CO2) in your blood. Changes in your CO2 level could signal many medical conditions. Bicarbonate levels go down if you have kidney failure, a chronic lung problem or a serious infection. Low bicarbonate levels indicate acid buildup in your body that can be life-threatening.
Chloride
Normal range: 96 mEq/L to 106 mEq/L. Kidney problems can affect the ability to maintain a good chloride balance. High chloride can indicate too much acid in the body, a condition called metabolic acidosis. Some medications, such as those that treat glaucoma, and excessive use of laxatives can cause higher-than-normal chloride.
Liver function components
These enzymes and other proteins reflect how hard the liver is working to rid the body of toxins…
Liver enzymes
Looked at together, high levels of the enzymes ALT (alanine aminotransferase), AST (aspartate aminotransferase) and ALP (alkaline phosphatase) can suggest problems such as fatty liver disease, hepatitis, gallbladder conditions and liver failure. Your doctor may order an ultrasound of your liver to help make a diagnosis. Because ALP works with bones and the liver, a high level could be a sign of certain bone disorders…
ALT. Normal range: 4 international units per liter (IU/L) to 36 IU/L.
AST. Normal range: 8 IU/L to 33 IU/L.
ALP. Normal range: 44 IU/L to 147 IU/L.
Albumin
Normal range: 3.4 g/dL to 5.4 g/dL. This protein, which is important for healing, helps move calcium, vitamins and other substances through your blood. A low level can indicate kidney or liver disease or that your body isn’t getting enough protein or malnutrition. But too much protein in your diet or dehydration can cause a high level of albumin—high protein intake can cause kidney stones.
Total protein
Normal range: 6.0 g/dL to 8.3 g/dL. This is your albumin level plus and globulins, an important part of your immune system. A high number can signal chronic inflammation, including cancer and infections, whereas a low one can be a sign of malnutrition or liver disease, among others.
Bilirubin
Normal range: 0.1 mg/dL to 1.2 mg/dL. Bilirubin is a waste product made from the breakdown of red blood cells. Various liver problems and gallbladder disease can cause a rise as can infections such as the flu or mononucleosis.
Kidney function components
The kidneys are tasked with removing waste products. A buildup of the following can be a sign of kidney trouble…
BUN (blood urea nitrogen)
Normal range: 6 mg/dL to 20 mg/dL. Urea nitrogen results from the normal breakdown of proteins. A high BUN level is a clue that the kidneys are not removing protein properly. Elevated BUN levels also can be caused by gastrointestinal bleeding and dehydration. A low level can indicate you’re not eating enough protein but also can be a sign of liver failure.
Creatinine
Normal range: 0.6 mg/dL to 1.3 mg/dL. This is the waste product of creatine, a chemical that helps supply energy to your muscles. As with BUN, a high level points to a problem with the kidneys.
