Serum electrolyte panel

In medicine, a very commonly used cehmical determination of, minimally, the concentration of four physiologically related ions in the serum obtained from clotted blood: sodium, potassium, bicarbonate and chloride. Calcium is frequently reported as well.

The most common method is to take a sample is of venous blood that has been allowed to clot, then centrifuged to leave pure serum. If the clot lyses into the sample, the serum is useless for testing, for clot lysis will falsely elevate the potassium level. Alternative ways to get the same information include automated point of care analyzers, and, in the critical care setting, ion-selective electrodes in the patient's blood vessels.

Blood gas analysis complements the bicarbonate level with carbon dioxide values.

In clinical laboratories, it is usually performed by an automated analyzer. The serum electrolyte panel is a subset of the basic metabolic panel, which also measures glucose, blood urea nitrogen and creatinine; an automated analyzer often simultaneously determines all seven values. Increasingly, calcium ion concentration is being reported as an additional electrolyte, although phosphate and magnesium ions are still separately ordered.