Magnesium (serum) Blood Test Kit

Magnesium is an essential mineral that serves as a cofactor for over 300 enzyme systems in the body, regulating diverse biochemical reactions including protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. It's required for energy production (ATP synthesis), oxidative phosphorylation, glycolysis, and the structural development of bone. Magnesium also plays a crucial role in the active transport of calcium and potassium ions across cell membranes—a process critical for nerve impulse conduction, muscle contraction, and normal heart rhythm. The body contains approximately 25 grams of magnesium in an adult, with 50-60% stored in bones, 39-49% inside cells (particularly muscle and soft tissue), and only about 1% in blood and extracellular fluid. The kidneys primarily regulate magnesium balance, adjusting urinary excretion to match intake. Dietary sources include green leafy vegetables (spinach, kale), nuts (almonds, cashews), seeds (pumpkin, chia), whole grains, legumes, dark chocolate, avocados, bananas, and fish. Refined and processed foods tend to be low in magnesium. Magnesium deficiency (hypomagnesaemia) is more common than often recognised. Early symptoms can be subtle and non-specific: loss of appetite, nausea, fatigue, and weakness. As deficiency progresses, symptoms may include muscle cramps, spasms, or twitching (including eyelid twitches), numbness and tingling, personality changes, abnormal heart rhythms, and seizures. Chronic magnesium deficiency is associated with increased risk of hypertension, cardiovascular disease, type 2 diabetes, osteoporosis, and migraines. Risk factors for deficiency include gastrointestinal diseases (Crohn's, coeliac, chronic diarrhoea), type 2 diabetes, alcohol dependence, older age, and certain medications. Normal serum magnesium levels are typically 0.7-1.0 mmol/L (or 1.7-2.4 mg/dL). Levels below 0.7 mmol/L indicate deficiency. However, because serum levels are tightly regulated by the body, they can remain in the normal range even when total body stores are depleted—sometimes called "subclinical" or "chronic latent" magnesium deficiency. If you have symptoms or risk factors for deficiency with borderline-normal serum levels, a trial of magnesium supplementation may still be worthwhile. High serum magnesium (hypermagnesaemia) is rare and usually occurs only with kidney failure or excessive supplementation—symptoms include low blood pressure, nausea, flushing, and in severe cases, muscle weakness and cardiac arrest. Results outside the normal range may need a follow-up with your GP.