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HelpOrder Code MG_F Magnesium, Feces
Ordering Guidance
This test is only clinically valid if performed on watery specimens. In the event a formed fecal specimen is submitted, the test will not be performed.
Specimen Required
Patient Preparation: No barium, laxatives, or enemas may be used for 96 hours prior to start of, or during, collection.
Supplies: Stool containers - 24, 48, 72 Hour Kit (T291)
Container/Tube: Stool container
Specimen Volume: 10 g
Collection Instructions: Collect a very liquid stool specimen.
Useful For
Workup of cases of chronic diarrhea
Identifying the use of magnesium-containing laxatives contributing to osmotic diarrhea
Method Name
Colorimetric Titration
Reporting Name
Magnesium, FSpecimen Type
FecalSpecimen Minimum Volume
5 g
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Fecal | Frozen (preferred) | 14 days | |
| Refrigerated | 7 days | ||
| Ambient | 48 hours |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Reference Values
An interpretive report will be provided
Method Description
In an alkaline solution, magnesium forms a purple complex with xylidyl blue, a diazonium salt. The magnesium concentration is measured photometrically via the decrease in the xylidyl blue absorbance.(Package insert: Magnesium reagent. Roche Diagnostics; V8.0 01/2020)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
83735
Day(s) Performed
Monday, Thursday