Comprehensive Metabolic Panel (CMP): Results Explained
Everything you need to know about Comprehensive Metabolic Panel (CMP): Results Explained test results, including normal ranges and what abnormal levels might mean.
Reference Range
Unit: Panel (14 tests)Reference Range
Reference ranges vary by laboratory. Always consult your healthcare provider for interpretation of your specific results.
What is a Comprehensive Metabolic Panel?
The Comprehensive Metabolic Panel (CMP) is one of the most commonly ordered blood tests. It's a broad screening tool that gives doctors a bird's-eye view of your body's metabolism—how your organs are functioning and your chemical balance.
Think of the CMP as a routine maintenance check for your car. Instead of checking the oil, battery, and tires separately, the mechanic runs a comprehensive diagnostic. The CMP does the same for your body: it checks multiple systems in one efficient test.
The CMP measures 14 different components:
Glucose metabolism:
- Glucose (blood sugar)
Kidney function:
- BUN (Blood Urea Nitrogen)
- Creatinine
- eGFR (estimated Glomerular Filtration Rate)
Liver function:
- ALP (Alkaline Phosphatase)
- ALT (Alanine Aminotransferase)
- AST (Aspartate Aminotransferase)
- Bilirubin (Total)
- Albumin
- Total Protein
Electrolytes:
- Sodium
- Potassium
- Chloride
- Bicarbonate (CO2)
Why This Panel Matters
The CMP screens for diabetes, kidney disease, liver disease, and electrolyte imbalances. It's used for routine health screening, monitoring medication effects, and evaluating unexplained symptoms. Abnormal results guide further testing and treatment decisions.
Understanding Your Results
The CMP reports 14 individual values. Here's what each component measures and what abnormal results might indicate:
Glucose
What it measures: The amount of sugar in your blood after fasting.
Normal range: 70-100 mg/dL (fasting)
Glucose Interpretation
| Factor | Effect | What to Do |
|---|---|---|
| Elevated (100-125 mg/dL) | Increases | Prediabetes—lifestyle changes and monitoring recommended |
| High (≥126 mg/dL) | Increases | Diabetes range—confirm with additional testing |
| Low (<70 mg/dL) | Decreases | Hypoglycemia—may indicate medication excess, liver disease, or hormonal disorders |
Always tell your doctor about medications, supplements, and recent health events before testing.
Kidney Function Tests
BUN (Blood Urea Nitrogen)
- What it measures: Waste product from protein breakdown, filtered by kidneys
- Normal range: 7-20 mg/dL
- Elevated: Dehydration, kidney dysfunction, high protein intake, GI bleeding
- Low: Liver disease, malnutrition, overhydration
Creatinine
- What it measures: Waste product from muscle metabolism, filtered by kidneys
- Normal range: 0.7-1.3 mg/dL (varies by muscle mass)
- Elevated: Kidney dysfunction, dehydration, intense exercise
- Low: Low muscle mass, malnutrition
eGFR (estimated Glomerular Filtration Rate)
- What it measures: How well kidneys filter waste (calculated from creatinine, age, gender)
- Normal range: ≥90 mL/min/1.73m²
- 60-89: Mildly decreased kidney function
- 30-59: Moderate to severe kidney disease
- 15-29: Severe kidney disease
- ＜15: Kidney failure
Kidney Function Patterns
When BUN and creatinine are both elevated, it suggests reduced kidney filtration. If BUN is high but creatinine is normal, think dehydration (high BUN:creatinine ratio). Creatinine is more specific for kidney function than BUN alone.
Liver Function Tests
ALP (Alkaline Phosphatase)
- What it measures: Enzyme from liver and bone
- Normal range: 44-147 U/L
- Elevated: Liver obstruction, bone disease, pregnancy, healing fractures
ALT (Alanine Aminotransferase)
- What it measures: Liver-specific enzyme
- Normal range: 7-56 U/L
- Elevated: Liver cell injury (hepatitis, fatty liver, medications, alcohol)
AST (Aspartate Aminotransferase)
- What it measures: Enzyme from liver, muscle, heart
- Normal range: 10-40 U/L
- Elevated: Liver injury, muscle damage, heart attack
Bilirubin (Total)
- What it measures: Breakdown product of red blood cells
- Normal range: 0.3-1.2 mg/dL
- Elevated: Liver disease, bile duct obstruction, hemolysis (rapid red blood cell breakdown)
Albumin
- What it measures: Protein made by the liver
- Normal range: 3.5-5.0 g/dL
- Low: Malnutrition, liver disease, kidney disease, inflammation
- High: Dehydration (less common)
Total Protein
- What it measures: Total protein in blood (albumin + globulins)
- Normal range: 6.3-7.9 g/dL
- Low: Malnutrition, liver disease, kidney disease
- High: Dehydration, chronic inflammation, multiple myeloma
AST:ALT Ratio
Comparing AST to ALT helps identify liver disease causes. In alcoholic liver disease, AST is typically higher than ALT (AST:ALT ＞ 2:1). In viral hepatitis and fatty liver disease, ALT is usually higher than AST.
Electrolytes
Sodium
- What it measures: Main electrolyte outside cells
- Normal range: 136-145 mEq/L
- High (hypernatremia): Dehydration
- Low (hyponatremia): Fluid excess, kidney dysfunction, medications
Potassium
- What it measures: Main electrolyte inside cells
- Normal range: 3.5-5.0 mEq/L
- High (hyperkalemia): Kidney failure, medications (ACE inhibitors, spironolactone)
- Low (hypokalemia): Diuretics, vomiting, diarrhea, malnutrition
Chloride
- What it measures: Electrolyte that balances sodium
- Normal range: 98-107 mEq/L
- Usually follows sodium patterns
Bicarbonate (CO2)
- What it measures: Blood's acid-base balance
- Normal range: 22-29 mEq/L
- High: Metabolic alkalosis, lung dysfunction
- Low: Metabolic acidosis, kidney dysfunction, diarrhea
When is a CMP Ordered?
Doctors order CMPs for various reasons:
When Your Doctor Might Order a CMP
The CMP is a versatile test used for screening, diagnosis, and monitoring.
You're having a routine health checkup
The CMP is standard screening for adults over 40 or with risk factors. It detects early diabetes, kidney disease, and liver dysfunction before symptoms appear.
You're starting a new medication
Many medications affect liver or kidney function (statins, pain medications, antibiotics). A baseline CMP establishes normal and monitors for medication side effects.
You have unexplained fatigue or weakness
Fatigue can result from anemia, liver dysfunction, kidney disease, electrolyte imbalances, or diabetes. The CMP screens for many potential causes.
You have abdominal pain or yellowing of skin/eyes
These symptoms suggest possible liver or gallbladder disease. The CMP evaluates liver enzymes and bilirubin to assess liver function.
You're being monitored for known conditions
If you have diabetes, kidney disease, or liver disease, regular CMPs monitor disease progression and treatment effectiveness.
Interpreting Patterns
The CMP's power comes from seeing patterns across related tests:
Dehydration pattern:
- Elevated BUN with normal creatinine (high BUN:creatinine ratio ＞ 20:1)
- Elevated sodium
- Elevated total protein and albumin (hemoconcentration)
Kidney dysfunction pattern:
- Elevated BUN and creatinine both elevated (ratio ~10:1)
- Decreased eGFR
- May see electrolyte abnormalities (potassium elevation)
Liver cell injury pattern:
- Elevated ALT and AST (ALT higher than AST in non-alcoholic liver disease)
- Normal or mildly elevated ALP
- Normal bilirubin (early stages)
Liver obstruction pattern:
- Elevated ALP and bilirubin
- Normal or mildly elevated ALT/AST
- This pattern suggests bile duct blockage
Malnutrition or protein deficiency pattern:
- Low albumin and total protein
- May see low BUN
- Electrolytes may be abnormal
Context Matters
Abnormal CMP values never stand alone. Your doctor interprets them in context: your symptoms, medical history, medications, and other test results. Mild abnormalities may be insignificant in isolation but meaningful when combined with other findings.
Your Action Plan Based on Results
If all CMP components are normal:
- Continue regular health screening
- Repeat as recommended by your doctor (often annually)
- Maintain healthy lifestyle habits
- Be aware that normal results don't guarantee perfect health—screening continues
If you have mild abnormalities:
- Repeat testing to confirm results (lab variation occurs)
- Review medications with your doctor (some cause abnormalities)
- Lifestyle changes may address mild elevations (diet, exercise, alcohol reduction)
- Follow-up testing in 1-3 months typically recommended
If you have significant abnormalities:
- Additional testing to determine the cause
- May include ultrasound, CT scan, viral hepatitis testing, or other specialized tests
- Treatment depends on the underlying cause
- Referral to a specialist may be recommended (gastroenterologist, nephrologist, endocrinologist)
When CMP Abnormalities Require Urgent Evaluation
- Potassium above 6.0 mEq/L (dangerous heart rhythm risk)
- Sodium below 120 mEq/L or above 155 mEq/L (neurological symptoms)
- Creatinine suddenly elevated (acute kidney injury)
- ALT or AST above 1000 U/L (acute liver failure)
- Known liver or kidney disease with sudden worsening
⚠️ These abnormalities require prompt medical evaluation. Contact your doctor or seek urgent care, especially if accompanied by symptoms like confusion, weakness, decreased urine output, or jaundice.
Common Questions
Disclaimer: This information is for educational purposes only and does not constitute medical advice. Always consult your healthcare provider to interpret your CMP results and determine appropriate next steps.
Track Your Comprehensive Metabolic Panel Results
Monitor your levels over time, identify trends, and share your history with your doctor.