For God did not give us a spirit of cowardice but rather of power and love and self-control.
— 2 Timothy 1:7 (NABRE)

NCLEX-RN® Study Guides

NCLEX-RN® Lab Values

Free, reason-first guides to the lab values the NCLEX-RN® expects you to act on. Each guide covers the normal range, the critical values, and the priority nursing action — the decision the exam tests, not just the number to memorize.

Mariano Alfred Acevedo, PhD, RN Doctorally prepared nurse educator · Jade NursingPrep™ Updated July 2026

How these guides work

The NCLEX-RN® is designed to test clinical judgment, not just recall — so knowing a lab value is only the starting point. A stem can hand you a value and four plausible actions and ask what you would do first. Each guide below is built around that skill: the normal range and critical thresholds up front, the discrimination the exam wants (for example, high versus low), and the priority nursing action, worked through the N.U.R.S.E.S. Sequence™ so the order becomes reasoning instead of memorization.

The guides

Electrolytes Potassium Normal range, critical values, hyperkalemia vs hypokalemia, ECG changes, and the priority action when a value reads 6.8. Read the guide →

In development: Sodium, Calcium, Magnesium, Chloride, and renal function values (BUN and creatinine). New guides are added here as they publish.

A note on reference ranges: lab reference ranges vary slightly by laboratory and testing program. Always follow the values provided by your facility or testing source. These guides are for educational NCLEX-RN® preparation and are not medical advice.