Lab Values a PN Candidate Should Recognise on Sight

A practical nursing candidate does not need every number an RN candidate needs. That is not a lowered bar. It is a different job, and the list that matters most is the one where recognising a value changes what you do in the next few minutes.

Why the PN list is shorter

RN items ask you to interpret, correct and titrate. PN items ask you to recognise, report, monitor and assist. Different verbs, different lists.

If your job at the bedside is to notice that a value has crossed a line and get it in front of someone who can act on it, then the values worth knowing on sight are the ones that trigger that call. The rest can be looked up.

That difference in scope runs through the whole exam, not only the laboratory items. NCLEX-RN versus NCLEX-PN, what is actually different sets out where the two exams part company.

The panel you will see most often

Most of the laboratory values in a PN stem come off a basic metabolic panel. MedlinePlus publishes these adult reference ranges, and its own pages note that normal value ranges vary slightly among different laboratories.

• Sodium, 136 to 144 mEq/L
• Potassium, 3.7 to 5.2 mEq/L
• Chloride, 96 to 106 mmol/L
• Carbon dioxide, 23 to 29 mmol/L
• Blood urea nitrogen, 6 to 20 mg/dL
• Creatinine, 0.8 to 1.2 mg/dL
• Glucose, 64 to 100 mg/dL

Learn them as a panel rather than as seven separate flashcards. They arrive together, they move together, and reading them in order tells a story no single line tells on its own. The basic metabolic panel read line by line walks that reading order.

One caution on the glucose row. That is a panel reference range, not a diagnostic threshold for diabetes, and the two are not interchangeable.

Which of these means pick up the phone

Recognition only helps if an action is attached to it, so pair every value with what it changes.

• A potassium outside its range affects the heart, so it moves fast in the queue
• A sodium below its range changes how a patient thinks and how safely they can walk
• A creatinine drifting up alongside blood urea nitrogen points at the kidneys, and at every renally cleared drug on the chart
• A glucose well outside the panel range changes the immediate plan, in whichever direction it went

That pairing habit is the whole argument of how to study lab values without memorizing a wall. A number with nothing attached is trivia. A number with an action attached is nursing.

Two of those rows travel together, which is part of why the panel is read as a panel. A creatinine and a blood urea nitrogen drifting up in the same direction say something neither row says alone, and BUN and creatinine read together, not separately works that pairing through.

The values we are deliberately not giving you

Some familiar rows did not make this list, and their absence is on purpose.

Haemoglobin, haematocrit, white cell count, platelets and prothrombin time all carry reference ranges that differ by laboratory, and in some cases by sex, and the sources we could verify did not give us figures clean enough to print. So we will not print them. Read the range on your patient's own report, which is the range that governs anyway.

Total calcium is a stranger case still. Three authoritative sources publish three different normal ranges for it, and that disagreement is a lesson rather than an error. Total calcium, when three authorities print three ranges has the whole story.

Why ranges differ between laboratories at all, and how to phrase a range honestly when two study sources disagree, is covered in why reference ranges vary between laboratories.

Where this lands on the PN test plan

NCSBN's 2026 NCLEX-PN test plan puts Reduction of Risk Potential at 9 to 15% of the examination, with a note that content area distributions may differ up to plus or minus 3% in each category. Laboratory values sit inside that subcategory.

The wider shape of that subcategory, and what practical nursing scope looks like inside it, is in Reduction of Risk Potential through a practical nursing lens.

How to drill this list

Do not read the list. Rehearse it. Cover the numbers, say each value out loud with its unit, then say the one thing that value would make you do.

Then reverse it. Give yourself an action, such as holding a dose or calling the prescriber, and name the value that would have produced it. Working backwards catches the rows you recognise but cannot actually use.

Ten minutes of that beats an hour spent staring at a wall chart, because the exam never asks you to recite a range. It asks what you would do about one.

Units are part of the answer

A value without its unit is not an answer, and this is the easiest place to lose an item you actually knew. Potassium and sodium live in mEq/L. Creatinine, blood urea nitrogen and glucose live in mg/dL. Chloride and carbon dioxide on this panel are printed in mmol/L.

Notice that the panel itself mixes units across its rows. That is normal rather than a misprint, so read the unit on each line instead of assuming the whole panel shares one.

The same discipline applies out loud. Saying a potassium without its unit invites the person on the other end of the phone to guess which scale you mean, and guessing is how the wrong preparation gets pulled.

After you recognise it

Recognition is step one and it is not the finish line. Once you know a value is out of range, the next decision is whether it goes to the front of the queue or waits its turn, and that ordering is a skill of its own.

Which lab result do you report first works through that ranking, including why the value furthest from its reference range is often not the one reported first.

Learn the seven rows. Attach one action to each. Then practise saying them out loud with their units, because a value reported without its unit is not a report.