How to read potassium results
Other platforms explain it with text and video. In VMS you practice it on the patient.
Potassium keeps the heart beating in a normal rhythm. Both low and high levels can cause dangerous arrhythmias.
Step by step
Check if it is real
A hemolyzed sample, a tight tourniquet or fist clenching can falsely raise potassium. Repeat it if the result does not fit the patient. [1]
Get an ECG
For any significant low or high value, check an ECG. Low potassium can cause flat T waves and U waves; high potassium causes peaked T waves and wide QRS. [2]
Find the cause of low potassium
Common causes are diuretics, vomiting, diarrhea, insulin and albuterol. [2]
Replace low potassium safely
Give oral potassium when possible. IV potassium is always diluted and given by pump, never as an IV push. [3]
Check magnesium
Low magnesium makes low potassium hard to correct. Replace magnesium too. [2]
Find the cause of high potassium
Look for kidney failure, ACE inhibitors, ARBs, spironolactone, potassium supplements, acidosis and tissue breakdown. [2]
Treat dangerous high potassium
With ECG changes, give IV calcium first, then insulin with dextrose and albuterol, and remove potassium with binders, diuretics or dialysis. [1]
Common errors
- Giving IV potassium as a push.
- Treating a hemolyzed high result without repeating it.
- Not checking magnesium when potassium stays low.
Typical adult categories; use your lab's ranges [2]
| Potassium (mEq/L) | Category | Typical action |
|---|---|---|
| Under 2.5 | Severe low | Monitor the heart, replace urgently |
| 2.5 to 3.4 | Low | Replace, find the cause |
| 3.5 to 5.0 | Normal | None |
| 5.1 to 6.0 | Mild high | Repeat, stop causes, check ECG |
| Over 6.0 or any ECG change | Severe high | Emergency treatment |
Practice it in VMS
In VMS you do this on the patient, not on paper: every step goes on the checklist with a score, and in Teach mode Blocky tells you what comes next.
VMS cases that train this skill
Sources
- AAMC Core Entrustable Professional Activities (Core EPAs)
- NCCPA PANCE Content Blueprint
- Open RN, Nursing Pharmacology 2e (CC BY 4.0)
Facts and steps follow AAMC Core Entrustable Professional Activities (Core EPAs); NCCPA PANCE Content Blueprint. VMS is not affiliated with these organizations. Updated: 2026-10-11.