Intended use

The ISE module of the Roche/Hitachi cobas c systems is intended for the

quantitative determination of sodium, potassium and chloride in serum,

plasma or urine using ion‑selective electrodes.

Summary

Physiological significance:1

Electrolytes are involved in most major metabolic functions in the body.

Sodium, potassium and chloride 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.

Sodium is the major extracellular cation and functions to maintain fluid

distribution and osmotic pressure. Some causes of decreased levels of

sodium include prolonged vomiting or diarrhea, diminished reabsorption in

the kidney and excessive fluid retention. Common causes of increased

sodium include excessive fluid loss, high salt intake and increased kidney

reabsorption.

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.

Chloride is the major extracellular anion and serves to regulate the balance

of extracellular fluid distribution. Similarly to the other ions, common causes

of decreased chloride include reduced dietary intake, prolonged vomiting

and reduced renal reabsorption as well as some forms of acidosis and

alkalosis. Increased chloride values are found in dehydration, kidney failure,

some forms of acidosis, high dietary or parenteral chloride intake, and

salicylate poisoning.