Can this result diagnose a condition on its own?

No. Laboratory results are interpreted with symptoms, medical history, specimen conditions and related tests.

Which reference range should I use?

Start with the performing laboratory's own reference interval; clinical cutoffs, when relevant, are separate sourced thresholds used for a specific purpose.

When should I discuss the result with a healthcare professional?

Results that are clearly outside range, persistent, symptomatic or unexpected should be reviewed by a healthcare professional.

Information about a laboratory test

Potassium: What Does This Test Measure?

Measures blood potassium, an electrolyte essential for nerve, muscle and especially cardiac electrical function.

Test summary

Test name: Potassium
Abbreviations: K, K+
Category: Electrolytes / Cardiac & Renal
Panel: Electrolyte Panel / Basic Metabolic Panel
Specimen: Serum / plasma
Common units: mEq/L, mmol/L

What does the test measure?

Measures blood potassium, an electrolyte essential for nerve, muscle and especially cardiac electrical function.

Why is the test ordered?

Ordered as part of electrolyte testing to assess kidney function, medicine effects, acid-base balance and arrhythmia-related risk.

Information about a low result

Low potassium can occur with vomiting/diarrhea, diuretics, hormonal conditions or renal losses and may affect muscle and cardiac function.

Information about a high result

High potassium can occur with reduced kidney function, certain medicines, cell breakdown or sample hemolysis.

Reference and clinical context

Start with the performing laboratory's reference interval, unit and specimen conditions. Numeric information on this page is stored as sourced example intervals or clinical thresholds.

Reference range 1

>= 3.7 – <= 5.2 mmol/L

Population: Adults
Age range: 18
Specimen: Serum / plasma

Example adult Potassium reference interval

The source presents these values as a common example reference interval. Laboratory method, age and clinical context can change the range; the user's own report takes priority.

Reference ranges may vary by laboratory, method used, age, sex, pregnancy status, and clinical context. The reference range on your own laboratory report takes precedence.

Interpretation notes

Sample hemolysis can cause a falsely high result. Marked high or low potassium can be clinically important for cardiac rhythm.

Related specialties

Internal Medicine
Nephrology
Emergency Medicine
Cardiology

Frequently asked questions

More information about this test

Sources

Comprehensive Metabolic Panel — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Example adult intervals for ALT, AST, ALP, albumin, bilirubin, total protein, BUN, creatinine and electrolytes · Verified: Aug 12, 2026
Creatinine Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Creatinine limitations and use with eGFR, BUN and urine testing · Verified: Aug 12, 2026
Electrolyte Panel — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Sodium, potassium, chloride and bicarbonate as an electrolyte panel · Verified: Aug 12, 2026
Potassium Blood Test — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Potassium interpretation, kidney and medication context · Verified: Aug 12, 2026
Carbon Dioxide (CO2) in Blood — U.S. National Library of Medicine (MedlinePlus)
Government medical reference · 2026 · Serum total CO2/bicarbonate and acid-base context · Verified: Aug 12, 2026
Estimated GFR Calculators / Laboratory Evaluation — National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
U.S. government medical reference · 2026 · Creatinine-based eGFR, race-free CKD-EPI recommendation and limitations · Verified: Aug 12, 2026