Lab Values for NCLEX-RN

Introduction

  • Mark Klimek, a registered nurse, will discuss lab values for the NCLEX-RN exam.
  • Lab values are often seen as challenging due to memorization and varying ranges across resources.
  • The NCLEX will present lab values that are clearly within or outside the normal range, avoiding borderline cases.

Prioritizing Lab Values

  • The exam will provide four abnormal lab values and require prioritization.
  • A method exists to prioritize lab abnormalities without extensive memorization.

Lecture Outline

  • The lecture is structured in three columns:
    • Test/Lab Value
    • Range (Ballpark, generally accepted)
    • Prioritization

Key to Prioritization

  • A, B, C, and D are used to indicate the priority of lab abnormalities.
  • Important: These letters are for this lecture only and not recognized by NCLEX.

Priority Levels

  • A - Abnormal:
    • The lab value is abnormal, but not critical.
    • No immediate action is required.
  • B - Be Concerned:
    • The lab value is concerning.
    • No immediate action is required, but the nurse should be aware and monitor for potential causes.
  • C - Critical:
    • The lab value is critical, and action must be taken.
    • The healthcare provider needs to be notified eventually.
  • D - Deadly/Dangerous:
    • The lab value is deadly dangerous and requires immediate action.
    • The nurse cannot handle it alone and must call for help.
    • Assess the patient's alertness and orientation before calling for help.

Specific Lab Values

Creatinine

  • Third best indicator of kidney function.
    • Best: Glomerular Filtration Rate (GFR)
    • Second best: 24-hour creatinine clearance (urine test)
  • Range: 0.6 to 1.2 (same numbers as lithium therapeutic level, but unrelated)
  • Prioritization: A
    • Elevated creatinine indicates a kidney issue, but is not immediately life-threatening.
    • A high creatinine is only of immediate importance if the patient is scheduled for a test with contrast dye, as the kidneys excrete the dye.

PT INR

  • Used to monitor warfarin (Coumadin) therapy.
  • Range: 2s and 3s are desired for patients on warfarin (proper anticoagulation).
  • Prioritization:
    • 4 and above: C
      • Hold all warfarin.
      • Assess for bleeding.
      • Prepare to administer vitamin K (the antidote).
      • Call the health care provider.

Potassium (K+)

  • Range: 3.5 to 5.0 or 5.3 (upper limit varies slightly; NCLEX will not use borderline numbers)
  • Prioritization:
    • High (in the 5s): C
      • Hold all potassium.
      • If potassium IV is running, stop it.
      • Assess the heart (ECG changes).
      • Prepare to administer:
        • Dextrose 5% with Regular Insulin (D5W with Regular Insulin) in two different IV sites
        • Kayexalate
        • Albuterol
    • 6.0 and higher: D
      • Everything listed above must be done immediately and simultaneously.
      • Assess patient's alertness and orientation; call for help.

pH

  • Range: 7.35 to 7.45 (no debate on these numbers)
  • NCLEX focuses on low pH (acidosis).
  • Prioritization:
    • pH in the 6s or lower: D
      • Assess vital signs.
      • Call the health care provider immediately.

Blood Urea Nitrogen (BUN)

  • Waste product.
  • Range: Approximately 8 to 30 (varies among resources)
  • Prioritization: B
    • Elevated BUN indicates dehydration.

Hemoglobin (Hgb)

  • Range: 12 to 18 (slight gender difference, but NCLEX will not test on borderline numbers)
  • NCLEX usually tests low hemoglobin levels.
  • Prioritization:
    • 8 to 11: B
      • Assess for bleeding.
    • Below 8: C
      • Transfuse blood. (This may change in the future to below 7, but for this NCLEX, 8 is the cutoff).

Hematocrit (Hct)

  • Range: 36 to 54
  • Less likely to be tested than hemoglobin.
  • Prioritization: B if high
    • Assess for dehydration.

General Tip

  • If a lab value is high and the nurse has no clue what is causing it, suspect dehydration.

Carbon Dioxide (CO2) - pCO2

  • Range: 35 to 45 mmHg (millimeters of mercury)
  • Prioritization: High CO2 is the focus
    • In the 50s: C (Hypercarbia)
      • Assess the respiratory system.
      • Instruct the patient to do Pursed-Lip Breathing to prolong exhalation and remove excess CO2.
    • In the 60s and higher: D (Respiratory Failure)
      • Assess lungs, pursed-lip breathing
      • Prepare to intubate and ventilate
      • Call respiratory therapy
      • Call the health care provider

Oxygen (O2) - Arterial Blood Gas (ABG)

  • Range: 78 to 100
  • Prioritization:
    • Low, but in the 70s (70-77): C (Hypoxia)
      • Assess the lungs.
      • Administer oxygen.
    • In the 60s or lower: D (Respiratory Failure)
      • Assess the lungs.
      • Administer oxygen.
      • Prepare to intubate and ventilate.
      • Call respiratory therapy.
      • Call the healthcare provider

Oxygen Saturation (O2 Sat) - Finger Probe (SaO2)

  • Range: 93 to 100
  • Prioritization: Below 93
    • Hypoxia
      • Assess the lungs.
      • Administer oxygen.

Key Reminder for Respiratory Problems

  • When dealing with respiratory issues, the order of assess and intervene can be flipped.
  • In other words, you can administer oxygen first, then assess the patient's respiratory status.
  • This applies to the CO2 and O2 levels.