NCLEX-RN® Study Guides

NCLEX-RN® Lab Values (2026)

On the NCLEX-RN®, an item that gives you a numeric lab value also gives you its normal reference range. NCSBN® states this on the exam’s own site. The exam scores what you do with the number, not whether you memorized it.

These free guides are built for that. Each one gives the normal range and the critical values, then works the priority nursing action.

Mariano Alfred Acevedo, PhD, RN Founder and Curriculum Director · Jade NursingPrep™ Updated September 22, 2026

When an NCLEX-RN® item gives you a lab value, it also gives you the normal range. What it scores is what you do next. Read the full answer →

If your question is how to study lab values rather than whether to memorize them, start with how to study lab values for the NCLEX-RN®.

What lab values do you need to know for the NCLEX-RN®?

Start with the labs that carry a nursing action. Five of them have a full free guide here. You will also find a guide to ABG interpretation, a printable cheat sheet, and an answer on the exam format itself.

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 → 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 → Acid–base ABG interpretation The 4 steps in order, the ROME method, the 4 acid–base disorders at a glance, and how to tell uncompensated, partially compensated, and fully compensated gases apart. Read the guide → 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 → 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 →

In development: Calcium and Chloride. New guides are added here as they publish.

How these guides work

Every guide follows the same shape. It opens with the normal range and the critical values. It then draws the discrimination the exam leans on, usually high versus low. It closes on the priority nursing action, worked through the N.U.R.S.E.S. Sequence™.

The order is the point. A stem can hand you a value and four plausible actions. It then asks which one you would take first. Reading the number is only the first step.

Want more practice like this? Try the free NCLEX-RN® practice questions — rationale for every option, no sign-up required to start.

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.