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 nurses must be ready to act on. Each guide covers the normal range, the critical values, and the priority nursing action — the decision to make, not just the number to memorize.

Mariano Alfred Acevedo, PhD, RN Founder and Curriculum Director · Jade NursingPrep™ Updated August 2026

How these guides work

The NCLEX-RN® is designed to test how you reason and decide, not just what you 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 key discrimination (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 → Electrolytes Sodium Normal range, critical values, hypernatremia vs hyponatremia, SIADH, safe correction, and the priority action when a value reads 116. Read the guide → Electrolytes Magnesium Normal range, critical values, hypermagnesemia vs hypomagnesemia, the reflex check, and the priority action when the potassium won’t come up. Read the guide → Renal function Creatinine Adult reference example, the baseline and trend that decide the action, the BUN : creatinine ratio, and when a 0.3 mg/dL rise already meets AKI Stage 1. Read the guide → Exam format Does the NCLEX-RN® give you lab values? Yes — NCSBN® states items with a numeric lab value include the normal reference range. What the item hands you, what it asks of you, and what that means for how you study. Read the answer → Reference sheet Lab Values Cheat Sheet (2026) All eight labs on one printable sheet — the reference range, what the reading means, and the first nursing action. Free PDF, no sign-up. Get the sheet → Renal function BUN A published adult reference example, the three questions a high BUN asks, what a low BUN means, and why BUN is escalated as a pattern rather than a number. Read the guide →

In development: Calcium and Chloride. 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.