Question about RBC mag test

christinafriberg · Post by **christinafriberg** » Wed Dec 21, 2016 11:10 pm

Tex-I recently had blood drawn for the test. A half hour before the draw I had 50mg of Remag and earlier in the day 250mg topical magnesium. Will the oral or topical mag skew the test results?
Thanks-Christina

Post by **tex** » Thu Dec 22, 2016 9:04 am

Hi Christina,

Probably. It would definitely skew the results of a serum magnesium test to make it show a normal result despite a chronic magnesium deficiency. The RBC test result won't be affected as much as a serum test result would be, but there will surely be some effect. Here's what Walk-in-Lab says about this question:

Instructions

No fasting or other special preparation is required prior to giving blood for the red blood cell (RBC) blood test. Individuals are able to take their medications and dietary supplements as they normally would the morning of the test. Patients should let their doctor or the lab know before testing if they are taking a magnesium supplement, as this can affect test results.

http://www.walkinlab.com/heart-health-t ... dtest.html

My take on this is that it will probably raise the result by a few tenths of a point, but not enough to make the results meaningless. If it were a serum magnesium test, the results would be worthless.

Tex

christinafriberg · Post by **christinafriberg** » Thu Dec 22, 2016 4:55 pm

THANK YOU TEX! Eases my mind that I didn't just waste money on worthless lab work :-)