The Magnesium test is a blood test that measures the level of magnesium in the blood serum. Magnesium is the fourth most abundant mineral in the human body and the second most prevalent intracellular cation, playing a fundamental role in over 300 enzymatic reactions that govern energy production, protein synthesis, DNA replication, muscle contraction, nerve transmission, and blood glucose regulation. Approximately 60 percent of the body's magnesium is stored in bone, 39 percent within cells of soft tissues and muscles, and only about one percent circulates in the blood, which means serum magnesium levels can appear normal even when total body magnesium stores are significantly depleted.
Magnesium is essential for the normal function of the heart, kidneys, muscles, and nervous system. It regulates the activity of calcium and potassium channels, stabilises cardiac electrical conduction, and is required for the activation of Vitamin D and the proper functioning of parathyroid hormone. Deficiency is therefore associated with a broad spectrum of clinical consequences including cardiac arrhythmias, muscle cramps, tetany, seizures, and worsening of hypertension and diabetes.
In India, magnesium deficiency is increasingly recognised as a widespread but underdiagnosed nutritional problem, driven by diets low in green leafy vegetables, nuts, and whole grains, widespread use of proton pump inhibitors, prevalence of Type 2 diabetes, and high rates of chronic kidney disease and alcoholism. The test is performed on a small blood sample drawn from a vein and completed in under five minutes.