🧪 Lab Values
Normal Laboratory Values
Quick-reference normal ranges for the most commonly ordered laboratory tests in clinical practice.
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Complete Blood Count (CBC)
| Test / Parameter | Normal Range | Clinical Notes |
|---|---|---|
| WBC | 4.5–11.0 K/µL | Elevated: infection, inflammation. Low: neutropenia risk. |
| RBC | M: 4.7–6.1 M/µL F: 4.2–5.4 M/µL | Low: anemia. High: polycythemia. |
| Hemoglobin | M: 14–18 g/dL F: 12–16 g/dL | Transfuse if <7 g/dL (or <8 with cardiac disease). |
| Hematocrit | M: 42–52% F: 37–47% | Reflects hydration status. |
| Platelets | 150–450 K/µL | <50K: bleeding risk. <20K: spontaneous bleed risk. |
| Neutrophils (ANC) | 1.5–8.0 K/µL (≥1500 normal) | <500: neutropenic precautions. |
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Basic Metabolic Panel (BMP)
| Test / Parameter | Normal Range | Clinical Notes |
|---|---|---|
| Sodium (Na+) | 135–145 mEq/L | Hyponatremia: SIADH, diuretics. Hypernatremia: dehydration. |
| Potassium (K+) | 3.5–5.0 mEq/L | Critical: <2.5 or >6.5. Cardiac monitoring. |
| Chloride (Cl-) | 98–107 mEq/L | Follows sodium. Low: vomiting, GI losses. |
| CO2 (Bicarbonate) | 22–26 mEq/L | Acid-base indicator. Low: acidosis. High: alkalosis. |
| BUN | 7–20 mg/dL | High: dehydration, renal disease, GI bleed. |
| Creatinine | M: 0.7–1.3 mg/dL F: 0.6–1.1 mg/dL | Renal function marker. Rises with kidney injury. |
| Glucose | 70–99 mg/dL (fasting) | <70: hypoglycemia. >126: diabetes. >300: DKA risk. |
| Calcium (total) | 8.5–10.5 mg/dL | Low: hypocalcemia (tetany). High: malignancy, hyperparathyroid. |
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Liver Function Tests (LFTs)
| Test / Parameter | Normal Range | Clinical Notes |
|---|---|---|
| ALT | 7–56 U/L | Liver-specific. Elevated: hepatocellular injury. |
| AST | 10–40 U/L | AST > ALT: alcoholic liver disease. |
| Alk Phos | 44–147 U/L | Elevated: cholestasis, bone disease. |
| Bilirubin (total) | 0.1–1.2 mg/dL | Elevated: jaundice. Direct >0.4: obstructive. |
| Albumin | 3.5–5.0 g/dL | Low: liver disease, malnutrition, inflammation. |
| PT/INR | PT 11–13.5 sec INR 0.8–1.2 | Liver synthesizes clotting factors. High: liver disease. |
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Coagulation Studies
| Test / Parameter | Normal Range | Clinical Notes |
|---|---|---|
| PT/INR | PT 11–13.5 sec INR 0.8–1.2 | Warfarin target: INR 2.0–3.0 (2.5–3.5 for mechanical valve). |
| aPTT | 25–35 sec | Heparin target: 1.5–2.5× normal (46–70 sec). |
| Platelets | 150–450 K/µL | <50K: bleeding risk. <20K: ICH risk. |
| D-dimer | <0.5 µg/mL | Elevated: clot formation (DVT, PE, DIC). Non-specific. |
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Cardiac & Other
| Test / Parameter | Normal Range | Clinical Notes |
|---|---|---|
| Troponin I | <0.04 ng/mL | Elevated: myocardial injury. Peaks 12h, resolves 7–10 days. |
| BNP | <100 pg/mL | >400: heart failure likely. >900: severe HF. |
| Magnesium (Mg+) | 1.7–2.2 mg/dL | Low: arrhythmias. Replace slowly. |
| Phosphorus | 2.5–4.5 mg/dL | Low: refeeding syndrome, respiratory failure. |
| TSH | 0.4–4.0 mIU/L | High: hypothyroid. Low: hyperthyroid. |
labsCBCBMPLFTscoagulationreference ranges
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