📊 Chapter 770 · Reference Intervals for Laboratory Tests and Procedures

Nelson Textbook of Pediatrics 22nd Edition | Reference intervals: Gaussian (mean±2SD) vs non-Gaussian (2.5-97.5 percentile). Age, sex, Tanner stage partitioning. Key values: Bhutani bilirubin nomogram (hyperbilirubinemia risk), body surface area nomogram (dosing), BLL reference 3.5 μg/dL, CSF parameters, thyroid function tests.

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📋 30 Clinical Scenarios — Reference Intervals

📇 High‑Yield Review Cards

🩺 Clinical Recognition: Using Reference Intervals

Select a laboratory scenario to review appropriate reference intervals (Nelson Ch 770).

📋 Stepwise Approach to Reference Interval Interpretation

🔑 Key Principles — Chapter 770
• Gaussian distribution: Mean ± 2 SD (e.g., serum sodium).
• Non-Gaussian distribution: 2.5th to 97.5th percentile (e.g., creatine kinase, ALT).
• Age/sex partitioning essential – e.g., alkaline phosphatase higher in puberty (bone growth).
• Bhutani nomogram: Hour-specific bilirubin for hyperbilirubinemia risk assessment.
• Body surface area (BSA) nomogram: For chemotherapy/fluid dosing in children.

    ⚡ Reflex Prompts — Interpretation Decisions

    📖 Summary: Reference Intervals (Nelson 770)