Potassium, urine

Alternate test name

Potassium Random Urine, Potassium Timed Urine

Lab area

Clinical Biochemistry - General

Method and equipment

Equipment : Roche Cobas Pro ISE

Method : Test principle An Ion‑Selective Electrode (ISE) makes use of the unique properties of ion‑selective membrane to develop an electrical potential (electromotive force, EMF) for the measurements of ions in solution. Selective membrane is in contact with both the test solution and an internal filling solution. Due to the selectivity of the membrane, only the ions to be measured contribute to the EMF. The membrane EMF is determined by the difference in concentration of the test ion in the test solution and the internal filling solution. The EMF develops according to the Nernst equation for a specific ion in solution The complete measurement system for a particular ion includes the ISE, a reference electrode and electronic circuits to measure and process the EMF to give the test ion concentration. The sodium2,3 and potassium4 electrodes are based on neutral carriers and the chloride5 electrode is based on an ion exchanger

Expected turn-around time

Random Urine: STAT/Urgent: 4 Hours Routine: 24 Hours Timed Urine: STAT/Urgent/Rouine - 24 Hours

Shipping information

Background and clinical significance

The ISE analytical unit of the cobas c systems is intended for the quantitative determination of sodium, potassium and chloride in serum, plasma or urine using ion‑selective electrodes. Potassium measurements are used to monitor electrolyte balance in the diagnosis and treatment of disease conditions characterized by low or high blood potassium levels. Physiological significance:1 Electrolytes are involved in most major metabolic functions in the body. Sodium and potassium are amongst the most important physiological ions and the most often assayed electrolytes. They are supplied primarily through the diet, absorbed in the gastrointestinal tract, and excreted via the kidneys. 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.