NCLEX Lab Values 2026: The Complete Must-Know List (With Memory Tricks)

Lab values are one of the highest-yield, most predictable topics on the NCLEX. If you can recall the normal range, spot a critical value, and connect it to the right nursing action, you will pick up points on questions other students lose. This guide gives you the complete must-know list for the 2026 NGN exam, organized so it is easy to memorize and easy to apply.

How lab values are tested on the NGN

The Next Generation NCLEX rarely asks you to simply recite a number. Instead, it gives you a client scenario and asks what the value means and what you should do about it. So memorizing the range is step one. Step two, the part that earns points, is linking each abnormal value to an assessment finding and a nursing intervention.

Electrolytes

These show up constantly because they connect to cardiac, neuro, and renal questions.

  • Sodium: 135 to 145 mEq/L. Think neuro changes when it is off.
  • Potassium: 3.5 to 5.0 mEq/L. Think cardiac. High or low both cause dangerous dysrhythmias.
  • Calcium: 9.0 to 10.5 mg/dL. Think muscles and Chvostek and Trousseau signs when low.
  • Magnesium: 1.3 to 2.1 mEq/L. Often tracks with potassium and calcium.

Memory trick: potassium is the one most likely to kill quickly, so when a question gives you an abnormal potassium and asks what to do first, the cardiac monitor is almost always part of the answer.

Kidney and metabolic

  • BUN: 10 to 20 mg/dL
  • Creatinine: 0.6 to 1.2 mg/dL, the more specific kidney marker
  • Glucose (fasting): 70 to 100 mg/dL
  • Hemoglobin A1C: below 5.7 percent is normal, 6.5 percent or above is diabetes

Hematology and coagulation

  • Hemoglobin: roughly 12 to 18 g/dL depending on sex
  • Hematocrit: roughly three times the hemoglobin
  • Platelets: 150,000 to 400,000
  • INR: normal around 1, therapeutic 2 to 3 on warfarin
  • aPTT: watch this for heparin

Memory trick: PT and INR go with warfarin, aPTT goes with heparin. Match the drug to the test and you will not mix them up on exam day.

Arterial blood gases

ABGs deserve their own system because they are tested so heavily. If you want the full step-by-step method for interpreting them, read our guide on ABG interpretation using the ROME method, which walks through every scenario.

How to lock these in before exam day

Repetition with application is what makes lab values stick. The fastest way is to drill them inside full NGN-style questions so you practice the recall and the clinical judgment at the same time. Our 2026 NCLEX Ultimate Mastery Notes include every high-yield lab value with the mnemonics and the nursing actions attached, so you are learning the number and the response together.

Master your lab values and you remove one of the most reliable sources of lost points on the entire exam.

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