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Lab Values for NCLEX

Jun 9, 2025

Overview

This lecture covers the most important laboratory values that nurses need to know for the NCLEX exam, including ranges, significance, and common terms.

Complete Blood Count (CBC)

  • CBC assesses red blood cells (RBCs), white blood cells (WBCs), and platelets.
  • Normal RBC: 4.5–5.5 million.
  • Normal WBC: 5,000–10,000.
  • Normal platelets: 150,000–400,000.
  • Hemoglobin (female): 12–16 g/dL; Hemoglobin (male): 14–18 g/dL.
  • Hematocrit (female): 37–47%; Hematocrit (male): 42–52%.
  • Thrombocytopenia: platelets <150,000.
  • Leukopenia: WBC <5,000.

Coagulation Studies

  • PT (prothrombin time): 10–12 seconds not on anticoagulant.
  • INR (international normalized ratio): <1 (not on anticoagulant); 2–3 (on warfarin).
  • aPTT (activated partial thromboplastin time): 30–40 sec (not on heparin); 60–80 sec (therapeutic on heparin).

Metabolic Panels

  • Glucose: 70–100 mg/dL.
  • Calcium: 8.5–10.5 mg/dL.
  • Chloride: 95–105 mEq/L.
  • Magnesium: 1.5–2.5 mg/dL.
  • Phosphorus: 2.5–4.5 mg/dL.
  • Potassium: 3.5–5 mEq/L.
  • Sodium: 135–145 mEq/L.
  • BUN: 5–20 mg/dL.
  • Creatinine: 0.6–1.2 mg/dL.

Liver Function Tests

  • Total protein: 6.2–8.2 g/dL.
  • Albumin: 3.4–5.4 g/dL.
  • ALP: 40–120 U/L.
  • ALT: 7–56 U/L.
  • AST: 10–40 U/L.
  • Bilirubin: <1 mg/dL.

Lipid Panel

  • LDL: <100 mg/dL.
  • HDL: >60 mg/dL.
  • Total cholesterol: <200 mg/dL.
  • Triglycerides: <150 mg/dL.

Arterial Blood Gases (ABGs)

  • pH: 7.35–7.45.
  • PCO₂: 35–45 mmHg.
  • HCO₃ (bicarb): 22–26 mEq/L.
  • PO₂: 80–100 mmHg.
  • O₂ saturation: 95–100%.

Hemoglobin A1c

  • Normal (non-diabetic): 4–6%.
  • Diabetic goal: <7%.

Common Drug Levels

  • Digoxin: 0.5–2 ng/mL.
  • Carbamazepine: 4–10 µg/mL.
  • Dilantin (phenytoin): 10–20 µg/mL.
  • Theophylline: 10–20 µg/mL.
  • Phenobarbital: 15–40 µg/mL.
  • Lithium: 0.5–1.2 mmol/L.
  • Valproic acid: 50–100 µg/mL.

Key Terms & Definitions

  • CBC (Complete Blood Count) — Blood test measuring RBC, WBC, and platelets.
  • Thrombocytopenia — Low platelet count (<150,000).
  • Leukopenia — Low white blood cell count (<5,000).
  • PT/INR — Tests for blood clotting time; used for warfarin therapy.
  • aPTT — Test for clotting time; used for heparin therapy.
  • BUN — Blood urea nitrogen, indicator of kidney function.
  • Bilirubin — Pigment from RBC breakdown, high in liver dysfunction.
  • LDL/HDL — Types of cholesterol; LDL is "bad," HDL is "good."
  • Hemoglobin A1c — Average blood glucose over 3 months.
  • Therapeutic Drug Level — Safe/effective concentration of a medication.

Action Items / Next Steps

  • Take the free quiz on lab values.
  • Review the video on ABG interpretation (especially the tic-tac-toe method).

Full transcript