Magnesium
What it measures
Magnesium is a mineral that your muscles, nerves, and heart need. This test measures how much is in your blood.
When it’s ordered
Muscle cramps or weakness, irregular heartbeat, kidney disease, long-term use of water pills, and when other salt levels are off.
Medicare coverage
Medicare judges coverage case by case under its medical-necessity rules. Medicare does not publish a national list of diagnoses for this test. The local Medicare contractor in your state may have its own rules.
Typical price
Medicare pays a set rate of $6.70 for this test (2026 fee schedule). When Medicare covers this test, you pay nothing. A lab can bill far more if you pay on your own or if Medicare denies the claim, so ask for the price first.
One thing to watch
Ask your doctor why the test is ordered. The reason should be written on the lab order.
Look up the current Medicare allowable for Magnesium →
Rates and coverage rules shown apply to Original Medicare (Fee-for-Service) only. Medicare Advantage plans may differ. See our data sources →