Preferred Sample Type

Potassium (serum)

Suitable Specimen Types

  • Serum
  • Li Hep Plasma
1.0 mL blood (paediatric minimum volume 30 uL serum)

Sample Processing in Laboratory


Sample Preparation

Centrifuge - do not leave on cells overnight

Turnaround Time

1 day

Sample Stability


Potassium (serum)

General Information

Potassium is the main intracellular cation. Small changes in the distribution of potassium can give rise to medical emergencies. The serum and urine concentrations of potassium reflect a complex interplay of hormonal and other systems that regulate the intracellular content. The main regulators of potassium concentrations in serum and urine are, insulin, aldosterone, catecholamines and acid base status. Diseases of the kidney, adrenal and any process that affects acid base disturbance will affect plasma potassium concentration. Crush injuries are also a cause of hyperkalaemia.

High potassium concentrations can give rise to a medical emergency requiring rapid intervention. Changes in potassium concentration affect the electrical conductivity of muscles and cardiac muscle and in high concentrations can cause cardiac arrest.

Patient Preparation



Samples left on cells and haemolysed samples will not be analysed

Note: Insulin, corticosteroids, furosemide, thiazides can decrease potassium. Potassium sparing diurectics, ACE inhibitors can increase potassium.

Reference Range

Adult    3.5-5.3 mmol/L

Plasma Potassium Paediatrics

Neonates (<4weeks)   3.4-6.0 mmol/L

Infant (<1yr)   3.5-5.7 mmol/L

1-16yrs          3.5-5.0 mmol/L

(Source : Pathology Harmony Recommendations)


  • EQA Scheme?: Yes
  • EQA Status: