Comprehensive Metabolic Panel (CMP): All 14 Tests Explained with Normal Ranges

All 14 CMP Tests with Normal Ranges

The Anion Gap on Your CMP

A comprehensive metabolic panel includes an anion gap calculation to check whether acid is building up in the blood. The anion gap is not a separate blood test. According to the Cleveland Clinic, labs calculate it from the sodium, chloride, and carbon dioxide results on any basic metabolic panel, comprehensive panel, or electrolyte panel.

The calculation subtracts chloride and bicarbonate from sodium, with the carbon dioxide line on the panel representing bicarbonate. For example, if your sodium is 140 mEq/L, chloride is 104 mEq/L, and carbon dioxide is 24 mEq/L, your anion gap is 12 mEq/L. A typical anion gap is about 12 mEq/L, but there is no universal normal range. Each lab sets its own range based on its instruments, and modern analyzers tend to report lower values than older methods.

A high result most often signals metabolic acidosis from ketoacidosis (including diabetic ketoacidosis), lactic acidosis, kidney failure, or toxic ingestions. A low result is usually low albumin or a lab quirk. A high or low anion gap doesn't necessarily mean you have a medical condition. Read our full guide to learn what a high or low anion gap means.

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.

The guide to what a basic metabolic panel tests for covers the eight BMP tests, their ranges and why a doctor orders one.

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. A urinalysis showing glucose in the urine can also flag uncontrolled blood sugar worth following up.
• 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.

Cost, Insurance Coverage & Billing Codes

The CMP is billed under CPT code 80053. Cash-pay price without insurance typically runs $15–$60 at major reference labs such as Quest Diagnostics or Labcorp and direct-to-consumer ordering services — hospital-affiliated or in-office draws often bill considerably higher, sometimes $100+, before any insurance adjustment. Because the CMP is one of the most routine and inexpensive panels in lab medicine, most insurance plans cover it in full as part of an annual physical, a new-patient workup, or monitoring for a diagnosed condition (diabetes, hypertension, kidney disease) or a medication that affects the kidneys or liver (diuretics, ACE inhibitors, metformin, statins). If ordered purely as an elective or 'wellness' test outside a covered visit, some plans apply it to your deductible instead of covering it as preventive care — check your specific plan or ask the ordering office to bill it as part of your annual exam if you're trying to avoid an out-of-pocket charge. Quest Diagnostics and Labcorp each list the test under their own order names, often shown as CMP (14) or Comprehensive Metabolic Panel (14), but both bill under the same CPT code 80053. If the wording on an order form is unclear, confirm with Quest Diagnostics or Labcorp that the panel includes all 14 values described on this page before you pay.

CMP vs CBC: Two Different Panels

A complete blood count (CBC) is not part of a comprehensive metabolic panel (CMP). A CMP measures blood chemistry, including glucose, electrolytes, proteins, and markers for kidney and liver function. In contrast, a CBC counts physical blood cells. While clinicians frequently order both panels during a routine checkup, they are separate laboratory tests.

According to MedlinePlus, a CMP measures 14 substances. These include glucose, calcium, and electrolytes: sodium, potassium, bicarbonate, and chloride. The panel also tests albumin, total protein, bilirubin, liver enzymes (ALP, ALT, AST), and the kidney waste products BUN and creatinine. Clinicians use the CMP to evaluate liver and kidney health, blood glucose, protein levels, fluid and electrolyte balance, and metabolism. Fasting for several hours before the blood draw may be required.

A CBC measures the cells circulating in the bloodstream. It checks red blood cells, which carry oxygen, white blood cells, which fight infections, and platelets, which help blood clot. The test also measures hemoglobin, the iron-rich protein in red cells, hematocrit, the share of whole blood made of red cells, and MCV, the average size of red blood cells. Clinicians use a CBC to help diagnose blood diseases, infections, and immune system disorders, or to monitor conditions such as anemia and blood cancers. Further details appear in the CBC blood test guide and the overview on blood test results.

Iron, TIBC, and ferritin are not part of a CMP; the iron panel test guide covers what those three measure together.

Where to Find Metabolic Panel Test Kits