Comprehensive Metabolic Panel (CMP): All 14 Tests Explained with Normal Ranges
Medically reviewed by Medical Advisory Board Last reviewed 2026-05-13
Glucose, electrolytes, kidney function, liver enzymes, and protein — one draw, 14 answers
The CMP is a 14-test panel that checks glucose, electrolytes (sodium, potassium, chloride, CO2), kidney markers (BUN, creatinine, eGFR), liver enzymes (ALT, AST, ALP, bilirubin), and proteins (albumin, total protein). Here's what every value means.
The comprehensive metabolic panel — often abbreviated CMP or 'chem-14' — is one of the most commonly ordered blood tests in the United States. A single blood draw produces 14 values that screen four organ systems simultaneously: kidneys, liver, blood sugar metabolism, and fluid/electrolyte balance. It's the workhorse panel of annual physicals, hospital admissions, and medication monitoring.
The CMP builds on the basic metabolic panel (BMP), which includes 8 tests — glucose plus 7 electrolyte and kidney markers. The CMP adds 6 liver and protein values. If you see 'BMP' on your lab order, it's a CMP minus the liver tests. Understanding which tests are included in each panel helps you know what's being checked — and what's not.
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| Test | Normal Range | What It Checks | Also in BMP? |
|---|---|---|---|
| Glucose | 70 – 100 mg/dL (fasting) | Blood sugar; screen for diabetes/prediabetes | Yes |
| Sodium (Na) | 136 – 145 mEq/L | Fluid balance, nerve/muscle function | Yes |
| Potassium (K) | 3.5 – 5.0 mEq/L | Heart rhythm, muscle/nerve function | Yes |
| Chloride (Cl) | 98 – 106 mEq/L | Fluid balance, acid-base status | Yes |
| CO2 (Bicarbonate) | 23 – 29 mEq/L | Acid-base balance | Yes |
| BUN | 7 – 20 mg/dL | Kidney function, hydration | Yes |
| Creatinine | Men: 0.7 – 1.3 / Women: 0.6 – 1.1 mg/dL | Kidney function (muscle metabolism byproduct) | Yes |
| Calcium | 8.5 – 10.5 mg/dL | Bone health, parathyroid, muscle function | Yes |
| ALT | 7 – 56 U/L | Liver cell damage (most liver-specific) | No |
| AST | 10 – 40 U/L | Liver, heart, and muscle damage | No |
| ALP | 44 – 147 U/L | Bile duct/bone disorder screening | No |
| Bilirubin | 0.1 – 1.2 mg/dL | Liver processing of hemoglobin breakdown | No |
| Albumin | 3.5 – 5.5 g/dL | Liver synthetic function, nutrition status | No |
| Total Protein | 6.0 – 8.3 g/dL | Albumin + globulins; immune/liver function | No |
CMP vs BMP: Which One Do You Need?
The BMP includes 8 of the 14 CMP tests — glucose, electrolytes (Na, K, Cl, CO2), BUN, creatinine, and calcium. It's a quick metabolic snapshot commonly used in emergency departments and for patients on medications that affect kidneys or electrolytes (diuretics, ACE inhibitors, metformin).
The CMP adds ALT, AST, ALP, bilirubin, albumin, and total protein — making it a better choice for annual physicals, new patient workups, and monitoring medications that affect the liver (statins, methotrexate, acetaminophen). The cost difference is typically $5–15, so most doctors default to the CMP for more complete information.
Key Patterns to Recognize
- Fasting glucose 100–125 mg/dL: Prediabetes range. Pair with A1C testing and fasting insulin for a complete picture. See our insulin resistance guide.
- BUN/creatinine ratio >20:1: Suggests dehydration, GI bleeding, or high-protein diet rather than intrinsic kidney disease. Isolated creatinine elevation? See our kidney function guide.
- ALT > AST with both <300 U/L: Classic pattern for non-alcoholic fatty liver disease (NAFLD/MASLD), the most common cause of mildly elevated liver enzymes in the US. See our liver function test guide.
- AST > ALT (especially AST/ALT ratio >2): Suggests alcohol-related liver damage or cirrhosis.
- Low albumin (<3.5 g/dL): Poor nutrition, chronic liver disease, nephrotic syndrome, or chronic inflammation. Albumin is a late-stage marker — it drops after significant disease progression.
- Hypercalcemia (>10.5 mg/dL): Most commonly primary hyperparathyroidism or malignancy. Always confirm with repeat measurement and check albumin-corrected calcium.
Fasting Requirements
Most labs require 8–12 hours of fasting before a CMP because glucose values are only interpretable in the fasting state. Water, black coffee, and medications (unless instructed otherwise) are typically fine during the fasting window. Schedule an early morning draw to minimize the inconvenience.
If you ate before the test: your glucose will be elevated but the other 13 values remain accurate. Some labs will flag 'non-fasting' and your doctor may ask you to repeat just the glucose portion.
Frequently Asked Questions
What is a comprehensive metabolic panel?
A comprehensive metabolic panel (CMP) is a blood test that measures 14 substances: glucose (blood sugar), 4 electrolytes (sodium, potassium, chloride, CO2), 3 kidney markers (BUN, creatinine, calcium), 4 liver values (ALT, AST, ALP, bilirubin), and 2 proteins (albumin, total protein). It screens kidney function, liver function, blood sugar, and electrolyte balance in a single blood draw.
What is the difference between CMP and BMP?
A BMP (basic metabolic panel) includes 8 tests — glucose, electrolytes, BUN, creatinine, and calcium. A CMP adds 6 more tests covering liver function (ALT, AST, ALP, bilirubin) and protein levels (albumin, total protein), for a total of 14 tests. The CMP gives a more complete picture and is preferred for annual checkups. The BMP is often used for quick metabolic checks or electrolyte monitoring.
Do you need to fast for a comprehensive metabolic panel?
Yes, typically 8-12 hours of fasting is recommended because the CMP includes fasting glucose. Water is fine during the fast. If you accidentally eat, the glucose result will be elevated but the other 13 values remain accurate. Your doctor may ask you to repeat just the glucose if the non-fasting value is borderline.
What does a comprehensive metabolic panel test for?
A CMP tests four organ systems: (1) kidney function — BUN, creatinine, and eGFR tell you how well your kidneys filter waste; (2) liver function — ALT, AST, ALP, and bilirubin screen for liver damage or bile duct problems; (3) metabolism — glucose screens for diabetes/prediabetes; (4) electrolyte and fluid balance — sodium, potassium, chloride, CO2, and calcium affect heart rhythm, nerve function, and hydration.
What are the 14 tests in a comprehensive metabolic panel?
The 14 tests are: glucose, sodium, potassium, chloride, carbon dioxide (bicarbonate), BUN (blood urea nitrogen), creatinine, calcium, ALT (alanine aminotransferase), AST (aspartate aminotransferase), ALP (alkaline phosphatase), bilirubin, albumin, and total protein. Some labs also calculate eGFR from creatinine, though this is a calculated value rather than a directly measured 15th test.
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