24 Hour Urine Magnesium

You should get a 24-hour urine magnesium test if your blood magnesium is low and the cause is unclear, or if you have muscle cramps, twitching, weakness, irregular heartbeat, or recurrent kidney stones. It is also recommended for people taking diuretics, PPIs, or certain chemotherapy drugs, and those with alcohol use or malabsorption.

To prepare for a 24-hour urine magnesium test, discard your first morning urine and note the time. Then collect all urine for the next 24 hours, including the next morning's first sample, and keep the container refrigerated. Follow your usual diet, and inform your doctor about magnesium supplements, antacids, laxatives, or diuretics, as you may need to pause them.

No, fasting is not required for a 24-hour urine magnesium test. You should eat your usual diet during the collection period unless your doctor advises otherwise. Drink fluids normally, collect every urine sample over the full 24 hours, and inform your doctor about any magnesium supplements or laxatives you take.