The comprehensive metabolic panel (CMP) is a blood test measuring 14 substances providing information about overall metabolic health, kidney function, liver function, electrolyte balance, and blood sugar. CMP is one of the most commonly ordered blood tests and a standard annual test for adults with diabetes. The measures include glucose, calcium, sodium, potassium, chloride, bicarbonate (CO2), blood urea nitrogen (BUN), creatinine, eGFR (estimated glomerular filtration rate), albumin, total protein, alkaline phosphatase, ALT (alanine aminotransferase), AST (aspartate aminotransferase), and bilirubin. Different from basic metabolic panel (BMP) which has 8 measures (no liver enzymes), CMP is preferred for adults with diabetes because it includes liver function tests — non-alcoholic fatty liver disease (NAFLD) affects 50-70% of adults with type 2 diabetes. Key measures for diabetes monitoring: glucose (fasting 70-99 normal, 100-125 prediabetes, ≥126 diabetes on 2 occasions), eGFR (under 60 indicates CKD; affects medication dosing especially metformin and SGLT2 inhibitors), creatinine (kidney dysfunction marker), potassium (affected by ACE inhibitors, spironolactone), ALT/AST (elevation suggests fatty liver). ADA recommends CMP at least annually; more frequently with kidney disease, recent medication starts, or elevated liver enzymes.
CMP Components and Normal Ranges
| Test | Normal Range (Adult) | Diabetes Significance |
|---|---|---|
| Glucose (fasting) | 70-99 mg/dL | 100-125 prediabetes; ≥126 diabetes |
| Calcium | 8.5-10.2 mg/dL | Bone health; low with vitamin D deficiency |
| Sodium | 136-145 mEq/L | Affected by hydration, some meds |
| Potassium | 3.5-5.0 mEq/L | Affected by ACE inhibitors, diuretics |
| Chloride | 96-106 mEq/L | Acid-base balance |
| Bicarbonate (CO2) | 23-29 mEq/L | Acid-base; low in DKA |
| BUN | 7-20 mg/dL | Kidney function; dehydration |
| Creatinine | 0.6-1.2 mg/dL (M); 0.5-1.1 (F) | Kidney function |
| eGFR | ≥60 mL/min/1.73 m² | ≥90 normal; 60-89 mild reduction; under 60 CKD |
| Albumin | 3.5-5.0 g/dL | Protein status |
| Total protein | 6.0-8.3 g/dL | Overall protein |
| Alkaline phosphatase | 44-147 IU/L | Liver or bone |
| ALT | 7-56 U/L (M); 7-45 (F) | Liver enzyme; elevated in NAFLD |
| AST | 10-40 U/L | Liver enzyme; less specific than ALT |
| Total bilirubin | 0.1-1.2 mg/dL | Liver function |
Key Diabetes Measures
- Glucose: fasting; diagnostic for diabetes; monitor with A1C separately.
- eGFR: kidney function; affects medication choices.
- Creatinine: confirms kidney function status.
- BUN/Creatinine ratio: distinguishes dehydration from kidney issues.
- Potassium: medication effects monitored.
- ALT/AST: fatty liver screening — elevated in NAFLD.
- Albumin: nutritional status.
What Elevated ALT/AST Means in Diabetes
- Non-alcoholic fatty liver disease (NAFLD) — 50-70% of adults with T2D have NAFLD.
- NASH (non-alcoholic steatohepatitis) — more advanced; can progress to cirrhosis.
- Metformin can elevate liver enzymes mildly (typically minor).
- Statins can mildly elevate ALT.
- Acetaminophen overuse — significant elevations.
- Alcohol-related liver disease.
- Hepatitis B or C.
- FIB-4 score calculation uses AST + age + ALT to estimate liver fibrosis.
- Persistent elevation warrants further evaluation (FibroScan, hepatologist consultation).
eGFR and CKD Staging
| Stage | eGFR (mL/min/1.73 m²) | Description |
|---|---|---|
| Stage 1 | ≥90 | Normal; kidney damage present (proteinuria) |
| Stage 2 | 60-89 | Mild reduction |
| Stage 3a | 45-59 | Mild-moderate reduction |
| Stage 3b | 30-44 | Moderate-severe reduction |
| Stage 4 | 15-29 | Severe reduction |
| Stage 5 | under 15 | Kidney failure (dialysis or transplant needed) |
How to Prepare for CMP
- Fast 8-12 hours before test (water allowed).
- Schedule for morning to minimize fasting impact.
- Continue regular medications (unless specifically instructed otherwise).
- Note timing of last metformin dose if relevant.
- Avoid extreme exercise day before test.
- Bring list of medications.
- Bring previous lab results for comparison.
- Discuss results with healthcare provider — don’t interpret alone.
- Don’t smoke immediately before (can affect some measures).
- Tell phlebotomist if you have small or difficult veins.
Frequency Recommendations
- Adults with diabetes: annually at minimum.
- Adults with CKD stage 3 or higher: every 6 months.
- Adults with elevated ALT/AST: every 6 months.
- Adults starting new medications affecting kidneys/liver: within 3 months.
- Adults on metformin with reduced kidney function: every 3-6 months.
- Adults on diuretics, ACE inhibitors, ARBs: every 6-12 months for potassium.
- Adults with electrolyte abnormalities: more frequently.
- Pregnant women with diabetes: trimester monitoring as ordered.
The Bottom Line
The comprehensive metabolic panel (CMP) is a blood test measuring 14 substances providing information about overall metabolic health, kidney function, liver function, electrolyte balance, and blood sugar. CMP is one of the most commonly ordered blood tests and a standard annual test for adults with diabetes. Measures include glucose, calcium, sodium, potassium, chloride, bicarbonate, BUN, creatinine, eGFR, albumin, total protein, alkaline phosphatase, ALT, AST, and bilirubin. CMP is preferred over basic metabolic panel (BMP, 8 measures) for adults with diabetes because it includes liver function tests — NAFLD affects 50-70% of adults with type 2 diabetes. Key measures for diabetes monitoring: glucose (fasting), eGFR (kidney function affects medication dosing especially metformin and SGLT2 inhibitors — discontinue metformin if eGFR under 30), creatinine, BUN, potassium (affected by ACE inhibitors and diuretics), ALT/AST (NAFLD screening). eGFR staging: ≥90 normal, 60-89 mild reduction, 30-59 CKD, under 30 severe CKD or kidney failure. Elevated ALT/AST suggests NAFLD, NASH, alcohol-related liver disease, hepatitis, or medication effects; FIB-4 score (using AST + age + ALT) estimates liver fibrosis; persistent elevation warrants hepatologist evaluation. Preparation: fast 8-12 hours, morning appointment, continue regular medications, list of meds, previous lab results for comparison. ADA recommends CMP at least annually for adults with diabetes; more frequently with kidney disease, elevated liver enzymes, recent medication changes, or on diuretics/ACE inhibitors. For adults with type 2 diabetes, CMP provides essential routine surveillance across multiple organ systems. See our broader diabetes detection guide for context.
