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Minerals

Potassium levels: what do they tell you about your electrolyte balance?

Potassium is an essential electrolyte and mineral that helps regulate heartbeat, muscle contractions, nerve signals, and fluid balance. It is one of the most important minerals for cardiovascular health.

Turnaround 48 hours, estimate Turnaround: up to 48 hours after your blood draw (estimate).

Reference Ranges

See the value that applies to you:

Choose male or female — this range differs by sex.

Enter your age — this range changes with age.

This range also depends on context such as cycle phase or sample material; the highlighted rows apply to your group.

Your reference range
mmol/l
3,4 5,2 mmol/l
Reference ranges by group, in mmol/l
6 years and older · Plasma 3,4–4,9 mmol/l
3,4 4,9
6 years and older · Serum 3,8–5,2 mmol/l
3,8 5,2
3,4 5,2 mmol/l

Serum reads higher than plasma because platelets release potassium during clotting.

Source: NVKC Reference population: Dutch general-practice population (NUMBER, n = 7,574,327)

Reference values can vary between laboratories. Discuss your results with your GP for explanation and treatment decisions.

Potassium: what this test measures

This test measures the level of potassium in your blood. Even small changes in potassium levels can significantly affect heart rhythm and muscle function.

Potassium: why this value matters

Potassium is critical for maintaining heart rhythm, blood pressure regulation, and proper muscle function. Both low and high levels can be dangerous and may require medical attention. Consult your healthcare provider for interpretation.

Potassium: how the blood test works

Referral
No GP referral needed. After the order we arrange the referral through ZorgDomein, within one business day; orders after 17:00 or at the weekend start on the next business day. ZorgDomein emails a barcode, and that barcode is what the draw site needs.
The draw
A blood draw from a vein in the arm, at a partner laboratory's draw site. No home kit, no finger prick.
Results
Turnaround: up to 48 hours after your blood draw (estimate).
Where
650+ draw sites run by independent laboratories across the Netherlands. Draw sites

Potassium: when is testing worthwhile?

Testing may be recommended as part of routine health screening, if you take blood pressure medications, have kidney disease, or experience symptoms such as muscle weakness or heart palpitations.

Potassium: symptoms of a high or low value

Low Levels

Symptoms of low potassium may include muscle weakness, cramps, fatigue, constipation, and heart rhythm irregularities. Severe deficiency can be life-threatening.

High Levels

High potassium may cause muscle weakness, tingling, nausea, and dangerous heart rhythm disturbances. It requires prompt medical evaluation, especially in those with kidney disease.

Potassium: lifestyle and this value

Include potassium-rich foods such as bananas, potatoes, spinach, avocados, and beans in your diet. If you take medications that affect potassium, work with your healthcare provider on monitoring.

Potassium: frequently asked questions

Why is potassium important for the heart?

Potassium helps regulate the electrical signals that control heartbeat. Both too little and too much potassium can cause dangerous heart rhythm problems.

Can medications affect potassium levels?

Yes, certain blood pressure medications, diuretics, and other drugs can raise or lower potassium. Always inform your healthcare provider about all medications you take.

What is the best food source of potassium?

Bananas are well-known, but potatoes, beans, spinach, avocados, and yoghurt are also excellent sources. A varied diet typically provides adequate potassium.

Potassium: sources

  1. den Elzen WPJ, Brouwer N, Thelen MH, Le Cessie S, Haagen I-A, Cobbaert CM. NUMBER: standardized reference intervals in the Netherlands using a 'big data' approach. Clin Chem Lab Med 2018;57(1):42-56. (retrieved 2026) doi.org

Tests with related values

These panels measure values from the same category as this marker.

Turnaround 48 hours, estimate

Full blood test

Twenty values from one draw: liver, kidneys, lipids, glucose, blood count, thyroid, iron and inflammation.

ALT (Alanine Aminotransferase) AST (Aspartate Aminotransferase) ALP (Alkaline Phosphatase) GGT (Gamma-Glutamyl Transferase) Creatinine eGFR (Estimated Glomerular Filtration Rate) Total Cholesterol HDL Cholesterol LDL Cholesterol Triglycerides Glucose (Fasting) Hemoglobin Hematocrit Erythrocytes (RBC) Leukocytes (WBC) MCV (Mean Corpuscular Volume) Platelets (Thrombocytes) TSH (Thyroid Stimulating Hormone) Ferritin CRP (C-Reactive Protein)
€199,-

Results without a doctor's assessment

You receive your values with the unit and reference range. A doctor's assessment is not part of this site. Discuss your results with your GP for explanation and treatment decisions.

Potassium

€7,-