Serum Magnesium

Serum magnesium testing is covered for conditions and exposures associated with hypomagnesemia—including certain antiarrhythmic drugs, long-term TPN, malabsorption, diuretic-induced renal loss, cisplatin, amphotericin, anti‑EGFR therapy, persistent hypocalcemia, unexplained lethargy/confusion, pregnancy-related conditions (e.g., pre-eclampsia), and cardiac arrhythmias. Specified monitoring frequencies include monthly (TPN, stabilized malabsorption, oral magnesium with renal impairment), every 2–3 weeks (nasogastric suction >5 days), approximately every six months (certain antiarrhythmics and persistent hypocalcemia), and annual checks for asymptomatic chronic conditions; routine monitoring is not indicated for chronic mental health diagnoses and evidence is mixed for hematologic disorders such as sickle cell disease or thalassemia.

"Measure serum magnesium in patients receiving quinidine, procainamide, or disopyramide (Norpace) approximately every six months while on therapy."