Corrected Magnesium Calculator

Magnesium supports neuromuscular signaling, cardiac rhythm, energy metabolism, bone health, and many enzyme reactions. A routine serum magnesium test measures total magnesium, including free ions and magnesium bound to proteins or complexed with anions. Albumin carries part of circulating magnesium. When albumin is low, measured total magnesium can fall even when the biologically active fraction is less affected. This calculator applies a simple conventional-unit adjustment: measured magnesium plus 0.2 times the difference between 4.0 g/dL and serum albumin. A low albumin value raises the corrected estimate, while albumin above the reference point lowers it. The displayed interpretation uses a general serum magnesium interval of 1.7 to 2.2 mg/dL. Laboratories use different methods and ranges, so the interval printed with the actual test remains authoritative. Unlike calcium correction, albumin-adjusted magnesium is not standardized or universally recommended. Published equations use different coefficients, units, and patient populations. A corrected value should therefore be treated as an educational estimate, not a replacement for measured serum magnesium, ionized magnesium, or clinical judgment. The equation shown on this page is important because applying a coefficient intended for mmol/L or albumin in g/L to conventional units can produce a misleading result. Magnesium balance depends strongly on kidney function and gastrointestinal absorption. Low values can occur with diarrhea, malnutrition, alcohol use, uncontrolled diabetes, proton-pump inhibitors, diuretics, or renal wasting. High values are less common with normal kidneys but may occur in kidney impairment, excessive supplementation, or magnesium-containing medications. Potassium and calcium abnormalities often accompany magnesium disorders and can be difficult to correct until magnesium is addressed. Use total magnesium and albumin from the same sample. Do not start, stop, or change supplements or medicines based only on this estimate. Symptoms such as severe weakness, confusion, seizures, fainting, breathing difficulty, or an abnormal heartbeat require prompt medical assessment. Clinicians interpret magnesium alongside symptoms, electrocardiography, kidney function, medication history, and repeat laboratory testing. The calculator is best used to understand how protein binding could influence a total result and to support an informed discussion with a healthcare professional.