red blood cell magnesium

The Magnesium, RBC (Red Blood Cell Magnesium) test measures intracellular magnesium levels, providing a more accurate assessment of true magnesium status than standard serum magnesium testing. Because most magnesium is stored inside cells rather than in the bloodstream, RBC magnesium helps identify functional deficiencies that may contribute to muscle cramps, fatigue, headaches, sleep disturbances, heart rhythm irregularities, and stress-related symptoms. This test is especially useful for evaluating long-term magnesium balance and guiding targeted supplementation for optimal nerve, muscle, and metabolic health.