Comprehensive Metabolic Panel (CMP): What It Measures, Normal Ranges & Results

What Is a CMP?

A Comprehensive Metabolic Panel is a routine blood test that evaluates how well the kidneys and liver are working, checks blood sugar levels, and measures important electrolytes. It is one of the most commonly ordered lab panels and gives healthcare providers a detailed look at overall metabolic health.

The CMP builds on the Basic Metabolic Panel (BMP) by adding six liver-related tests. While a BMP covers glucose, calcium, electrolytes, and kidney markers, the CMP adds ALT, AST, ALP, bilirubin, albumin, and total protein. This makes it a more comprehensive screening tool for detecting problems with the liver, kidneys, or metabolism.

Fasting for 8 to 12 hours is typically required before a CMP because eating can affect glucose and certain other values. Water is usually permitted. The test involves a standard blood draw, and results are generally available within 24 hours.

What Does a CMP Measure?

The 14 components of a CMP are grouped by the organ system or function they assess.

Blood Sugar

Glucose

The body's primary energy source. Fasting glucose is a key screening tool for diabetes and prediabetes. Levels above 126 mg/dL on two separate tests may indicate diabetes, while levels between 100 and 125 mg/dL could suggest prediabetes.

Typical range: 70 – 99 mg/dL (fasting)

Kidney Function

Creatinine

A waste product from normal muscle metabolism that the kidneys filter out. Elevated creatinine may indicate reduced kidney function. It is often used alongside BUN to calculate the estimated glomerular filtration rate (eGFR).

Typical range: Men: 0.74 – 1.35 mg/dL • Women: 0.59 – 1.04 mg/dL

Blood Urea Nitrogen (BUN)

Measures urea nitrogen in the blood, a waste product from protein breakdown. High BUN may suggest kidney problems, dehydration, or a high-protein diet. The BUN-to-creatinine ratio helps distinguish between kidney and non-kidney causes.

Typical range: 6 – 20 mg/dL

Electrolytes

Sodium (Na)

Regulates fluid balance, blood pressure, and nerve function. Low sodium (hyponatremia) may result from excess fluid intake, kidney problems, or certain medications. High sodium (hypernatremia) often points to dehydration.

Typical range: 136 – 145 mEq/L

Potassium (K)

Essential for heart rhythm, muscle contractions, and nerve signals. Both high and low potassium levels can be dangerous and may affect heart function. Diuretics, kidney disease, and dietary imbalances are common causes of abnormal levels.

Typical range: 3.5 – 5.0 mEq/L

Chloride (Cl) & Carbon Dioxide (CO2)

Chloride works with sodium to maintain fluid balance and acid-base equilibrium. CO2 (bicarbonate) reflects the body's acid-base status. Together, these markers help detect metabolic acidosis, alkalosis, and respiratory issues.

Typical ranges: Chloride: 98 – 106 mEq/L • CO2: 23 – 29 mEq/L

Calcium (Ca)

Critical for bone health, muscle function, nerve signaling, and blood clotting. Abnormal calcium levels may point to parathyroid disorders, kidney disease, vitamin D deficiency, or bone conditions.

Typical range: 8.5 – 10.5 mg/dL

Liver Function

ALT (Alanine Aminotransferase)

An enzyme found mainly in the liver. ALT is one of the most specific markers for liver damage. Elevated levels may indicate hepatitis, fatty liver disease, medication side effects, or alcohol-related injury. Comparing ALT to AST helps narrow the diagnosis.

Typical range: 7 – 56 U/L

AST (Aspartate Aminotransferase)

Found in the liver, heart, muscles, and other tissues. AST is less liver-specific than ALT, so elevated levels could also indicate muscle damage or heart problems. The AST-to-ALT ratio can help distinguish between alcohol-related and non-alcohol-related liver disease.

Typical range: 10 – 40 U/L

ALP (Alkaline Phosphatase)

An enzyme found in the liver and bones. Elevated ALP may suggest bile duct obstruction, liver disease, or bone disorders. It is normally higher in children and adolescents due to bone growth.

Typical range: 44 – 147 U/L

Bilirubin (Total)

A yellowish substance produced when red blood cells break down. The liver processes bilirubin for removal. High levels can cause jaundice (yellowing of the skin and eyes) and may indicate liver disease, bile duct problems, or hemolytic anemia.

Typical range: 0.1 – 1.2 mg/dL

Proteins

Albumin & Total Protein

Albumin is the most abundant blood protein and is produced by the liver. Low albumin may indicate liver disease, kidney disease (where protein leaks into urine), malnutrition, or chronic inflammation. Total protein includes both albumin and globulins and reflects overall protein status.

Typical ranges: Albumin: 3.5 – 5.0 g/dL • Total Protein: 6.0 – 8.3 g/dL

CMP Reference Ranges at a Glance

Reference ranges may vary by laboratory, testing method, age, sex, and other factors. Always use the ranges provided on the lab report.

Component	Men	Women	Units
Glucose (fasting)	70 – 99		mg/dL
BUN	6 – 20		mg/dL
Creatinine	0.74 – 1.35	0.59 – 1.04	mg/dL
Sodium	136 – 145		mEq/L
Potassium	3.5 – 5.0		mEq/L
Chloride	98 – 106		mEq/L
CO2 (Bicarbonate)	23 – 29		mEq/L
Calcium	8.5 – 10.5		mg/dL
ALT	7 – 56		U/L
AST	10 – 40		U/L
ALP	44 – 147		U/L
Bilirubin (Total)	0.1 – 1.2		mg/dL
Albumin	3.5 – 5.0		g/dL
Total Protein	6.0 – 8.3		g/dL

When Is a CMP Ordered?

A healthcare provider may order a CMP for many reasons, including:

Annual health screenings to check overall metabolic function
Monitoring diabetes by tracking fasting glucose levels over time
Evaluating kidney function in people with high blood pressure, diabetes, or urinary symptoms
Assessing liver health when jaundice, abdominal pain, or medication side effects are suspected
Checking electrolyte balance in people taking diuretics or other medications that affect fluid levels
Pre-surgical evaluation to ensure organ function before anesthesia
Following up on abnormal results from a previous basic metabolic panel

What Abnormal Results May Mean

Abnormal CMP values need to be interpreted in context. A single out-of-range result does not necessarily indicate disease. Healthcare providers look at patterns across multiple markers, along with symptoms and medical history.

High Values May Indicate

High glucose: Diabetes, prediabetes, stress response, or corticosteroid use
High BUN/creatinine: Kidney disease, dehydration, high-protein diet, or urinary obstruction
High sodium: Dehydration, Cushing syndrome, or excessive salt intake
High potassium: Kidney disease, medications (ACE inhibitors), or tissue breakdown
High ALT/AST: Liver inflammation, hepatitis, fatty liver, medications, or alcohol use
High bilirubin: Liver disease, bile duct obstruction, or hemolytic anemia
High calcium: Hyperparathyroidism, certain cancers, or excessive vitamin D

Low Values May Indicate

Low glucose: Hypoglycemia from insulin, medications, liver disease, or prolonged fasting
Low sodium: Overhydration, SIADH, kidney disease, or diuretic use
Low potassium: Diuretics, vomiting, diarrhea, or certain hormonal disorders
Low albumin: Liver disease, kidney disease (nephrotic syndrome), malnutrition, or chronic inflammation
Low calcium: Vitamin D deficiency, hypoparathyroidism, or kidney disease
Low CO2: Metabolic acidosis, kidney disease, or diabetic ketoacidosis

Frequently Asked Questions

What does a CMP blood test include?

A CMP includes 14 tests: glucose, calcium, sodium, potassium, chloride, CO2, BUN, creatinine, albumin, total protein, ALP, ALT, AST, and bilirubin. These evaluate blood sugar, electrolyte balance, kidney function, and liver function.

What is the difference between a CMP and a BMP?

A Basic Metabolic Panel (BMP) includes 8 tests covering glucose, calcium, electrolytes, and kidney function. A CMP includes all BMP tests plus 6 additional tests for liver function (ALT, AST, ALP, bilirubin) and protein levels (albumin, total protein). If liver evaluation is not needed, a healthcare provider may order a BMP instead.

Is fasting required before a CMP?

Yes, fasting for 8 to 12 hours is typically required before a CMP because food intake can affect glucose and some other results. Water is usually permitted. A healthcare provider will give specific fasting instructions.

What does a high creatinine level mean?

Elevated creatinine may indicate impaired kidney function, dehydration, high-protein diet, or intense exercise. Persistently elevated creatinine levels warrant further evaluation, often with additional tests like GFR (glomerular filtration rate). The BUN-to-creatinine ratio can help distinguish kidney from non-kidney causes.

What does a high ALT level mean?

A high ALT level may indicate liver inflammation or damage. Common causes include fatty liver disease, hepatitis, certain medications, and alcohol use. ALT is often evaluated alongside AST and other liver markers. The ALT-to-AST ratio can help determine the type of liver condition.

What causes abnormal electrolyte levels?

Abnormal electrolyte levels (sodium, potassium, chloride, CO2) may result from dehydration, kidney disease, certain medications (like diuretics), hormonal imbalances, or dietary factors. Severe imbalances can affect heart rhythm, muscle function, and nerve signaling.

How often should a CMP be performed?

For healthy adults, a CMP is commonly included in annual health screenings. People with chronic conditions like diabetes, kidney disease, or liver disease may need more frequent testing — sometimes every 3 to 6 months — as determined by a healthcare provider.

What is the difference between ALT and AST?

Both are liver enzymes, but ALT is found primarily in the liver, making it a more specific marker for liver damage. AST is found in the liver, heart, muscles, and other organs, so elevated AST alone could indicate damage to any of those tissues. Comparing the two through the ALT vs AST ratio helps narrow the diagnosis.

Related Tests and Conditions

CMP Biomarkers

Glucose Creatinine BUN Sodium Potassium Calcium ALT AST

Comparisons

BUN vs Creatinine ALT vs AST

Related Panels

CBC Panel Lipid Panel Thyroid Panel

Related Conditions

Diabetes Blood Tests Kidney Blood Tests Liver Blood Tests

Sources

MedlinePlus. Comprehensive Metabolic Panel (CMP). U.S. National Library of Medicine.
Lab Tests Online. Comprehensive Metabolic Panel. American Association for Clinical Chemistry.
Mayo Clinic. Comprehensive metabolic panel. Mayo Foundation for Medical Education and Research.
Cleveland Clinic. Comprehensive Metabolic Panel (CMP).
National Kidney Foundation. Understanding Your Lab Values.