A comprehensive metabolic panel (CMP) includes 14 blood tests that measure your blood sugar, electrolyte balance, kidney function, and liver health in a single draw. It’s one of the most commonly ordered lab panels, used for routine checkups and to monitor chronic conditions like diabetes or kidney disease.
The 14 Tests at a Glance
The CMP covers four categories of body chemistry. Here’s the full list:
- Blood sugar: Glucose
- Electrolytes: Sodium, potassium, chloride, carbon dioxide (bicarbonate)
- Kidney markers: Blood urea nitrogen (BUN), creatinine, calcium
- Liver markers: Albumin, total protein, alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin
If you’ve seen a “basic metabolic panel” (BMP) on your lab orders, that’s the shorter version. A BMP includes only the first eight tests: glucose, the four electrolytes, BUN, creatinine, and calcium. The CMP adds six liver-related tests on top of that.
Glucose
This measures the sugar circulating in your blood at the time of the draw. A normal fasting level falls between 70 and 100 mg/dL. Results above 100 may point toward prediabetes, and levels at or above 126 mg/dL on two separate tests typically indicate diabetes. Because food directly raises blood sugar, your doctor will usually ask you to fast before a CMP so this number reflects your baseline.
Electrolytes
Four electrolytes appear on the panel, each playing a distinct role in keeping your cells, nerves, and muscles working properly.
Sodium (normal: 135 to 145 mEq/L) is the main mineral controlling how much water your body holds onto. It regulates fluid balance and helps nerve and muscle cells fire correctly. Low sodium can cause confusion, nausea, or muscle cramps. High sodium often signals dehydration or a kidney problem.
Potassium (normal: 3.7 to 5.2 mEq/L) is critical for heart rhythm and muscle contraction. Even small shifts outside the normal range matter, because potassium that’s too high or too low can cause dangerous irregular heartbeats. Certain blood pressure medications can push potassium up or down, which is one reason doctors recheck this number regularly.
Chloride (normal: 96 to 106 mEq/L) works alongside sodium to maintain fluid balance and plays a role in digestion. Abnormal chloride levels often move in tandem with sodium and can reflect dehydration, vomiting, or kidney issues.
Carbon dioxide (normal: 23 to 29 mEq/L) is measured as bicarbonate, a form your body uses to buffer acid in the blood. The kidneys are the main regulators. A low reading can mean your blood is too acidic, while a high reading suggests it’s too alkaline. Lung disease, kidney disease, and severe vomiting or diarrhea can all shift this number.
Kidney Markers
BUN (normal: 6 to 20 mg/dL) measures a waste product called urea that your kidneys filter out. When kidney function declines, BUN rises because less waste is being cleared. Dehydration, a high-protein diet, and certain medications can also push BUN up, so it’s rarely interpreted alone.
Creatinine (normal: 0.6 to 1.3 mg/dL) is a waste product from normal muscle metabolism. Like BUN, it rises when the kidneys aren’t filtering efficiently. But creatinine is considered a more reliable marker of kidney function because it’s less affected by diet. Many labs will automatically use your creatinine result, along with your age and sex, to calculate an estimated glomerular filtration rate (eGFR). This gives you a more practical number: how many milliliters of blood your kidneys can filter per minute. An eGFR above 90 is normal, while values below 60 for three months or longer indicate chronic kidney disease.
The ratio between BUN and creatinine also provides useful information. A ratio near 10:1 suggests an issue within the kidneys themselves, while a ratio closer to 20:1 points to something reducing blood flow to the kidneys, like dehydration or heart failure.
Calcium (normal: 8.5 to 10.2 mg/dL) is grouped with the kidney markers because the kidneys help regulate calcium levels. Calcium is essential for bone strength, nerve signaling, and muscle contraction. Abnormal calcium can reflect problems with the parathyroid glands, vitamin D levels, kidney disease, or certain cancers.
Liver Markers
Six of the 14 tests evaluate how well your liver is working. They fall into two categories: proteins your liver produces and enzymes that leak into the blood when liver cells are stressed or damaged.
Proteins
Albumin (normal: 3.4 to 5.4 g/dL) is the most abundant protein in your blood and is made by the liver. It carries hormones, vitamins, and medications through the bloodstream and helps prevent fluid from leaking out of blood vessels. Low albumin can indicate liver disease, kidney disease that causes protein loss in urine, malnutrition, or chronic inflammation.
Total protein (normal: 6.0 to 8.3 g/dL) combines albumin with globulins, a group of proteins involved in immune function. A drop in total protein can suggest liver or kidney problems. An increase sometimes points to chronic infection or an immune system disorder.
Enzymes and Bilirubin
ALT (normal: 4 to 36 U/L) is found primarily in liver cells and is one of the most specific markers of liver injury. When liver cells are damaged by infection, medication, alcohol, or fatty liver disease, ALT spills into the bloodstream and levels rise.
AST (normal: 8 to 33 U/L) also rises with liver damage, but it’s less specific because it’s present in the heart and muscles too. Doctors often look at ALT and AST together. When both are elevated, the liver is the likely source. When AST is high but ALT is normal, muscle injury or a heart problem may be the cause.
ALP (normal: 20 to 130 U/L) is an enzyme found in the liver and bones. Elevated ALP can indicate a bile duct blockage, bone disorders, or, in some cases, normal bone growth in children and teenagers. It’s often paired with the other liver tests to narrow down the source.
Total bilirubin (normal: 0.1 to 1.2 mg/dL) is the yellowish waste product created when old red blood cells break down. Your liver processes bilirubin and sends it into bile for removal. High bilirubin can cause yellowing of the skin and eyes (jaundice) and may reflect liver disease, bile duct blockage, or conditions that destroy red blood cells faster than normal.
How to Prepare for the Test
Most providers ask you to fast for 8 to 12 hours before a CMP so the glucose reading is accurate. Water is generally fine during the fasting window. The blood draw itself takes a few minutes, and results typically come back within one to two business days. No special recovery is needed afterward.
Reading Your Results
Your lab report will list each of the 14 values alongside a reference range. These ranges can vary slightly between labs, so always compare your number to the range printed on your specific report rather than a generic chart. A single value slightly outside the range doesn’t necessarily signal a problem. Mild dehydration before the draw, a recent heavy meal (if you didn’t fully fast), or medications like blood pressure drugs or statins can nudge certain numbers up or down.
Patterns across multiple tests are more meaningful than any single result. For instance, elevated ALT, AST, and bilirubin together paint a clearer picture of liver stress than any one of those alone. Similarly, rising creatinine and BUN alongside a dropping eGFR tell a consistent story about kidney function. Your provider will interpret the panel as a whole, factor in your symptoms and medical history, and decide whether follow-up testing is needed.