💡 Tip: Reference intervals may vary slightly between laboratories. Always interpret results in the clinical context and compare with the local lab’s reference range. 🧬

🧫 Test	📏 Conventional Units	🌍 SI Reference Range
🩸 Alanine Aminotransferase (ALT, GPT)	10–40 U/L	10–40 U/L
🧬 Alkaline Phosphatase (ALP)	25–100 U/L	25–100 U/L
🥔 Amylase, serum	25–125 U/L	25–125 U/L
🧠 Aspartate Aminotransferase (AST, GOT)	12–38 U/L	12–38 U/L
🌈 Bilirubin, Total / Direct	0.1–1.0 mg/dL / 0.0–0.3 mg/dL	2–17 µmol/L / 0–5 µmol/L
🦴 Calcium (Total)	8.4–10.2 mg/dL	2.1–2.6 mmol/L
🫀 Cholesterol (Total)	< 200 mg/dL	< 5.2 mmol/L
💪 Creatinine	0.6–1.2 mg/dL	53–106 µmol/L
💧 Electrolytes
⚡ Sodium (Na⁺)	136–146 mEq/L	136–146 mmol/L
🧂 Chloride (Cl⁻)	95–105 mEq/L	95–105 mmol/L
🍌 Potassium (K⁺)	3.5–5.0 mEq/L	3.5–5.0 mmol/L
🫧 Bicarbonate (HCO₃⁻)	22–28 mEq/L	22–28 mmol/L
⚙️ Magnesium (Mg²⁺)	1.5–2.0 mEq/L	0.75–1.0 mmol/L
🫁 Arterial Blood Gases (Room Air)
🩸 PO₂	75–105 mmHg	10.0–14.0 kPa
💨 PCO₂	33–45 mmHg	4.4–5.9 kPa
⚖️ pH	7.35–7.45	[H⁺] = 36–44 nmol/L
🍬 Metabolic & Endocrine
🍭 Glucose (Fasting)	70–100 mg/dL	3.8–6.1 mmol/L
📈 Growth Hormone (Arginine Test)	< 5 ng/mL	< 5 µg/L
📊 Growth Hormone (Provocative Stimuli)	> 7 ng/mL	> 7 µg/L
💧 Osmolality, serum	275–295 mOsm/kg H₂O	275–295 mOsm/kg H₂O
🔋 Phosphate (Inorganic)	3.0–4.5 mg/dL	1.0–1.5 mmol/L
🧠 Prolactin (hPRL)	♂ <17 ng/mL / ♀ <25 ng/mL	♂ <17 µg/L / ♀ <25 µg/L
🧬 Proteins (Total)	6.0–7.8 g/dL	60–78 g/L
🎵 Albumin	3.5–5.5 g/dL	35–55 g/L
🌿 Globulins	2.3–3.5 g/dL	23–35 g/L
🧩 Thyroid Stimulating Hormone (TSH)	0.4–4.0 µU/mL	0.4–4.0 mIU/L
💥 Urea Nitrogen (BUN)	7–18 mg/dL	2.5–6.4 mmol/L
🧪 Uric Acid	3.0–8.2 mg/dL	0.18–0.48 mmol/L

🧠 Cerebrospinal Fluid (CSF) Reference Ranges

🔬 Test	📏 Conventional Units	🌍 SI Units
🧫 Cell Count	0–5 /mm³	0–5 ×10⁶/L
🍭 Glucose	40–70 mg/dL	2.2–3.9 mmol/L
🧬 Total Protein	< 40 mg/dL	< 0.40 g/L

🩸 Hematologic Reference Ranges

🩺 Test	📏 Conventional Units	🌍 SI Units
🧬 RBC Count	♂ 4.3–5.9 ×10⁶/mm³ / ♀ 3.5–5.5 ×10⁶/mm³	♂ 4.3–5.9 ×10¹²/L / ♀ 3.5–5.5 ×10¹²/L
🕒 ESR (Westergren)	♂ 0–15 mm/hr / ♀ 0–20 mm/hr	♂ 0–15 mm/hr / ♀ 0–20 mm/hr
❤️ Haemoglobin	♂ 13.5–17.5 g/dL / ♀ 12.0–16.0 g/dL	♂ 135–175 g/L / ♀ 120–160 g/L
🩸 Haematocrit	♂ 41–53% / ♀ 36–46%	♂ 0.41–0.53 / ♀ 0.36–0.46
🦠 WBC Count	4,500–11,000 /mm³	4.5–11.0 ×10⁹/L
📏 Mean Corpuscular Volume (MCV)	80–100 fL	80–100 fL
🧩 Platelet Count	150,000–400,000 /mm³	150–400 ×10⁹/L
🌱 Reticulocyte Count	0.5–1.5% of RBCs	0.5–1.5% of RBCs

💡 Educational Pearl: SI units (mmol/L, µmol/L, g/L) are now the international standard. For quick conversions: 1 mg/dL glucose ≈ 0.0555 mmol/L, 1 mg/dL urea ≈ 0.357 mmol/L, 1 mg/dL creatinine ≈ 88.4 µmol/L. Always check for lab-specific calibration and reference temperatures (usually 37 °C). 🌡️

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USMLE Lab Values

🧪 Blood, Plasma & Serum Reference Ranges

🧠 Cerebrospinal Fluid (CSF) Reference Ranges

🩸 Hematologic Reference Ranges

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