Chart — Lab
Metabolic Panel Interpretation Chart
BMP and CMP values organized by system — causes of abnormalities, critical thresholds, and required nursing actions for electrolytes, renal markers, glucose, liver enzymes, and proteins.
Educational use only. Reference ranges and critical thresholds vary by institution. BMP = electrolytes + BUN/Cr + glucose. CMP = BMP + liver markers + albumin + total protein. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Electrolytes (BMP + CMP)
| Test | Normal | Low (↓) Causes | High (↑) Causes | Critical | Nursing Action |
|---|---|---|---|---|---|
| Sodium (Na⁺) | 135–145 mEq/L | SIADH, diuretics, HF, cirrhosis, free water excess | Dehydration, DI, inadequate water intake, excess Na intake | < 120 or > 160 mEq/L | Neurological assessment; seizure precautions; controlled correction |
| Potassium (K⁺) | 3.5–5.0 mEq/L | Loop diuretics, vomiting, NG suction, alkalosis, steroids | AKI/CKD, acidosis, ACE inhibitors, cell death, hemolysis | < 2.5 or > 6.5 mEq/L | Continuous ECG monitoring; emergency treatment per order |
| Chloride (Cl⁻) | 98–106 mEq/L | Vomiting, NG suction, metabolic alkalosis, diuretics | Dehydration, metabolic acidosis, NS excess | Not routinely established as panic value | Correlate with Na and bicarbonate; assess for metabolic alkalosis |
| Bicarbonate (CO₂) | 22–29 mEq/L | Metabolic acidosis — DKA, lactic acidosis, diarrhea, renal failure | Metabolic alkalosis — vomiting, diuretics, antacid overuse | < 15 or > 40 mEq/L | Correlate with ABG if abnormal; identify underlying acid-base disorder |
Renal Markers (BMP + CMP)
| Test | Normal | Low (↓) Causes | High (↑) Causes | Critical | Nursing Action |
|---|---|---|---|---|---|
| BUN | 7–20 mg/dL | Liver failure (impaired urea synthesis), malnutrition, low protein intake | Pre-renal (dehydration/reduced perfusion most common), AKI, CKD, GI bleeding, high protein intake | Not standard; > 100 mg/dL warrants attention | Calculate BUN:Cr ratio; assess volume status; identify bleeding source |
| Creatinine | 0.6–1.2 mg/dL (M); 0.5–1.1 mg/dL (F) | Reduced muscle mass (elderly, malnutrition) — rarely significant | AKI, CKD, rhabdomyolysis, nephrotoxin exposure, reduced perfusion | Rise of > 0.3 mg/dL from baseline = AKI definition | Trend closely; hold nephrotoxins (NSAIDs, contrast, aminoglycosides, vancomycin); assess urine output |
Glucose (BMP + CMP)
| Test | Normal | Low (↓) Causes | High (↑) Causes | Critical | Nursing Action |
|---|---|---|---|---|---|
| Glucose (fasting) | 70–99 mg/dL (fasting); < 140 mg/dL (2h postprandial) | Insulin excess, sulfonylureas, adrenal insufficiency, prolonged fasting, sepsis | Diabetes, stress hyperglycemia, steroids, TPN, pancreatitis, infection | < 50 mg/dL (critical low); > 500 mg/dL (critical high) | < 50: D50W IV or glucagon IM IMMEDIATELY. > 500: notify provider, assess for DKA/HHS |
Liver Markers (CMP only)
| Test | Normal | Low (↓) Causes | High (↑) Causes | Critical | Nursing Action |
|---|---|---|---|---|---|
| ALT | 7–56 units/L | Not clinically significant | Hepatocellular injury (most specific liver enzyme) — viral hepatitis, NAFLD, drug toxicity, ischemia | > 3× ULN warrants investigation; > 10× = severe hepatocellular injury | Assess for jaundice, abdominal pain, RUQ tenderness; review medications for hepatotoxins |
| AST | 10–40 units/L | Not clinically significant | Liver damage, MI, skeletal muscle injury, rhabdomyolysis, myositis | Markedly elevated with ALT > AST = alcoholic hepatitis pattern | Not liver-specific — correlate with ALT, troponin, and CK to identify source |
| ALP | 44–147 units/L | Hypothyroidism, pernicious anemia, zinc deficiency — rarely significant | Cholestatic liver disease, bile duct obstruction, bone disease, pregnancy, Paget's disease | > 3× ULN with jaundice = biliary obstruction until proven otherwise | Check GGT (elevated with liver cause); assess for jaundice, clay-colored stools, dark urine |
| Total Bilirubin | 0.2–1.2 mg/dL | Not clinically significant | Liver disease, hemolysis (indirect), bile duct obstruction (direct), Gilbert syndrome | > 12 mg/dL = kernicterus risk in neonates; no standard adult panic value but high levels warrant urgent evaluation | Assess for jaundice (visible > 2–3 mg/dL); assess urine color (dark = bilirubinuria); stool color (pale = biliary obstruction) |
Proteins (CMP only)
| Test | Normal | Low (↓) Causes | High (↑) Causes | Critical | Nursing Action |
|---|---|---|---|---|---|
| Albumin | 3.5–5.0 g/dL | Malnutrition, liver failure (impaired synthesis), nephrotic syndrome, protein-losing enteropathy, inflammation | Dehydration (hemoconcentration) — rarely significant | < 2.0 g/dL = critical — affects drug binding, edema, wound healing | Apply corrected calcium formula; assess nutritional status; consider nutrition consult; assess for edema |
| Total Protein | 6.0–8.3 g/dL | Malnutrition, liver failure, nephrotic syndrome, protein-losing conditions | Dehydration; multiple myeloma (elevated globulin fraction) | Interpret with albumin — elevated total protein with normal albumin = high globulin (may indicate MM) | Calculate albumin-to-globulin ratio for further interpretation |
Key Interpretation Patterns
| Pattern | Lab Findings | Clinical Meaning |
|---|---|---|
| Pre-renal azotemia | BUN:Cr ratio > 20:1 | Dehydration or reduced renal perfusion — volume restore first |
| Hepatocellular injury | ALT > AST, markedly elevated transaminases | Viral hepatitis, drug toxicity, ischemic hepatitis |
| Alcoholic hepatitis | AST:ALT ratio > 2:1 (both < 300 units/L) | Classic pattern — AST rises more than ALT in alcohol-related liver injury |
| Cholestatic pattern | ALP and bilirubin elevated, ALT/AST relatively normal | Bile duct obstruction, primary biliary cholangitis, drug-induced cholestasis |
| High anion gap metabolic acidosis | Low bicarbonate; AG = Na − (Cl + HCO₃) > 12 mEq/L | MUDPILES causes: lactic acidosis (sepsis most common), DKA, uremia, salicylates |
| False low calcium | Low albumin with low total calcium | Corrected Ca = measured Ca + (0.8 × [4 − albumin]) — may be normal once corrected |
Related Resources
BMP & CMP ReferenceDetailed metabolic panel reference with interpretation pearls
Open →Interpreting Common Lab ValuesTrending, critical values, and clinical context
Open →Electrolyte Disorders: Clinical OverviewComprehensive guide to all 5 electrolyte disorders
Open →ABG Interpretation Step by StepAcid-base interpretation — bicarbonate in context of ABG
Open →Standards & sources
Fact-checked Jun 21, 2026This page is written to align with Standard laboratory reference ranges · Clinical & Laboratory Standards Institute (CLSI). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →