Serum magnesium refers to the amount of magnesium in your blood. It is a measurement that helps determine if you have low or high levels of magnesium in your body. Full definition
We often test serum magnesium levels and they are often low in diabetic patients. (idmprogram.com)
Migraine patients have presented with lower serum magnesium levels compared to normal control groups of the same age without migraine headaches. (mindbodygreen.com)
Could be true, but not sure how I'd validate it, as serum magnesium levels have little relation to total body levels (that which we care about). (peterattiamd.com)