Potassium (K)

Potassium (K)


In vitro test for the quantitative determination of potassium.

Submission Criteria: Specimen: Serum (preferred) or Plasma: Li-heparin only.

Minimum Volume: 2 mL

Container: Gold-top tube

Storage and Stability: Unseparated from cells:          2 hours

Separated from cells:                   14 days at 20-25ºC

14 days at 4-8ºC

365 days at -20ºC

Rejection Criteria: Rejection criteria include but are not limited to:

  1. Specimen containing fibrin or clots.
  2. Hemolyzed specimens
  3. Excessive platelet clumping
  4. Leaking specimens
  5. Substandard mixing or collection
  6. Expired or improperly stored collection tubes
  7. Improperly filled tubes based on collection tube manufacture’s guidelines.
  8. Contaminated specimens (IV fluid, foreign particles, etc.)
  9. Specimens not analyzed within the appropriate time frame.
  10. Samples not shipped at appropriate temperature. Samples without two proper identifiers or samples having identifiers that do not match the electronic or paper lab requisition.
Turnaround Time: 1 day
Clinical Significance: Potassium is the major intracellular cation and is critical to neural and muscle cell activity. Some causes of decreased potassium levels include reduced intake of dietary potassium or excessive loss of potassium from the body due to diarrhea, prolonged vomiting or increased renal excretion. Increased potassium levels may be caused by dehydration or shock, severe burns, diabetic ketoacidosis, and retention of potassium by the kidney.
Reference Ranges:
Normal: 3.6 – 5.2 mmol/L
Critical Value(s):  ≤ 2.5 mmol/L and ≥ 6.0 mmol/L

Ion-Selective Electrode (ISE) makes use of the unique properties of certain membrane materials develop an electrical potential (electromotive force, EMF) for the measurement of ions in solution.


Roche/Hitachi Cobas ISE