NCLEX Lab Values, Electrolytes & ABG Interpretation Made Easy
(Step-by-Step Guide) | Med-Surg Nursing Exam Prep 2026
This comprehensive nursing study guide simplifies the three most tested respiratory
and medical-surgical topics on ATI and NCLEX exams: Lab Values, Electrolytes
(Sodium, Potassium, Calcium), and ABG Interpretation.
Prepared for: Nursing Students (BSN / ADN / International)
Focus: Med-Surg | ATI | NCLEX-RN
Includes:
Normal lab ranges
Electrolyte imbalance recognition
ABG interpretation formula
Fluid Volume Disorders
Priority nursing actions
Exam tips and clinical scenarios
TABLE OF CONTENTS
1. Core Lab Values Review
2. Electrolytes Made Easy
3. ABG Step-by-Step Formula
4. Fluid Volume Disorders
5. Clinical Case Scenarios
6. NCLEX Priority Framework
7. Rapid Revision Cram Sheet
SECTION 1: LAB VALUES NCLEX REVIEW (COMPLETE GUIDE)
Know the Core Critical Labs:
Complete Blood Count (CBC)
Hemoglobin: 12–18 g/dL
Hematocrit: 37–52%
WBC: 5,000–10,000/mm³
Platelets: 150,000–400,000/mm³
1
, Why It Matters:
Low Hb → anemia → fatigue, hypoxia
High WBC → infection
Low platelets → bleeding risk
Electrolyte Panel (Basic Metabolic Panel)
Sodium: 135–145 mEq/L
Potassium: 3.5–5.0 mEq/L
Calcium: 8.6–10.2 mg/dL
Magnesium: 1.3-2.3 mEq/L
Phosphate: 2.5-4.5 mg/dL
Bicarbonate: 25-29 mEq/L
Chloride: 97-107 mEq/L
NCLEX Tip:
Always connect abnormal labs to:
1. Cardiac rhythm
2. Neurological status
3. Muscle function
Critical Thinking Pattern for Exams
If lab abnormal:
1. Is it life-threatening?
2. Does it affect heart rhythm?
3. What is the priority nursing action?
Example:
Potassium 6.2 → risk of arrhythmia → cardiac monitoring immediately.
SECTION 2: ELECTROLYTES MADE EASY (SODIUM, POTASSIUM,
CALCIUM)
1. SODIUM (135–145)
2
(Step-by-Step Guide) | Med-Surg Nursing Exam Prep 2026
This comprehensive nursing study guide simplifies the three most tested respiratory
and medical-surgical topics on ATI and NCLEX exams: Lab Values, Electrolytes
(Sodium, Potassium, Calcium), and ABG Interpretation.
Prepared for: Nursing Students (BSN / ADN / International)
Focus: Med-Surg | ATI | NCLEX-RN
Includes:
Normal lab ranges
Electrolyte imbalance recognition
ABG interpretation formula
Fluid Volume Disorders
Priority nursing actions
Exam tips and clinical scenarios
TABLE OF CONTENTS
1. Core Lab Values Review
2. Electrolytes Made Easy
3. ABG Step-by-Step Formula
4. Fluid Volume Disorders
5. Clinical Case Scenarios
6. NCLEX Priority Framework
7. Rapid Revision Cram Sheet
SECTION 1: LAB VALUES NCLEX REVIEW (COMPLETE GUIDE)
Know the Core Critical Labs:
Complete Blood Count (CBC)
Hemoglobin: 12–18 g/dL
Hematocrit: 37–52%
WBC: 5,000–10,000/mm³
Platelets: 150,000–400,000/mm³
1
, Why It Matters:
Low Hb → anemia → fatigue, hypoxia
High WBC → infection
Low platelets → bleeding risk
Electrolyte Panel (Basic Metabolic Panel)
Sodium: 135–145 mEq/L
Potassium: 3.5–5.0 mEq/L
Calcium: 8.6–10.2 mg/dL
Magnesium: 1.3-2.3 mEq/L
Phosphate: 2.5-4.5 mg/dL
Bicarbonate: 25-29 mEq/L
Chloride: 97-107 mEq/L
NCLEX Tip:
Always connect abnormal labs to:
1. Cardiac rhythm
2. Neurological status
3. Muscle function
Critical Thinking Pattern for Exams
If lab abnormal:
1. Is it life-threatening?
2. Does it affect heart rhythm?
3. What is the priority nursing action?
Example:
Potassium 6.2 → risk of arrhythmia → cardiac monitoring immediately.
SECTION 2: ELECTROLYTES MADE EASY (SODIUM, POTASSIUM,
CALCIUM)
1. SODIUM (135–145)
2
