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About This Test

Department: Biochemistry


  • Gel/clotted/lithium heparin (yellow/red/green top)

Add-on requests are accepted


Turnaround Time:

Within 24 hours


Part of urea and electrolyte profile

Elevated serum potassium concentration is commonly due to pre-analytical factors, including:

  • haemolysis
  • contamination with EDTA during venesection
  • delayed separation of plasma ('old' samples)
  • elevated platelet/white cell concentration

Lithium heparin plasma samples should only be used if a previous potassium result is suspected to be falsely raised due the patient having a high concentration of platelets or white cells. Lithium heparin samples can also be sent on renal patients to ensure the integrity of the sample.

If a lithium heparin sample is sent it is essential that a serum sample is also sent for any further biochemistry tests.

Reference ranges:

Age range Reference range (mmol/L)
All ages/sexes Serum 3.5 - 5.3
  Plasma 3.6 - 5.0

Derived from Pathology Harmony 2011

Results outside the reference range do not necessarily indicate disease. Similarly, results within the reference range do not preclude abnormality. Please contact the Duty Biochemist for discussion of individual patient results

Other Comments:

For more information, please see the following: Potassium - Lab Tests Online