Days Set Up
Analytic Time

8 hours

MiChart Code
Magnesium, 24 HR Urine
Soft Order Code

Test Updated:


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All specimens should be accompanied by a requisition.

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MLabs provides all the supplies necessary for the collection of specimens.

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Test Overview

Test Methodology

Colorimetric (Xylidyl Blue)

Test Usage

To aid in assessing cellular magnesium loss

Reference Range

50 - 200 mg/24 hrs (5-20 mMol/24 hrs). Random urine collections are reported in units of mg/dL, for which reference values are not established.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Onsite

24 hour urine collection. Instruct patient to void at 8:00am (or 8:00pm) and discard the specimen. Then collect all the urine including the final specimen voided at the end of the 24 hour collection period, i.e., 8:00am (or 8:00pm) the following day. Transport promptly to the laboratory. Container must be labeled with date and time collection started and finished. Refrigerate during collection.

Collection Offsite

Collect 24 hour urine in a clean, plastic container with no metal cap or glued insert and no preservative. Aliquot 5 mL urine into a clean, plastic container with no metal cap or glued insert and refrigerate. Record total 24 hour urine volume and collection dates/times on request form. Random urine also acceptable.

Normal Volume
5 mL aliquot of 24 hour urine collection or 2 mL aliquot of random urine collection.
Minimum Volume
2 mL aliquot of 24 hour urine collection or 1 mL aliquot of random urine collection.

Billing Information

CPT Code
Pro Fee Code
MAGU 35250-0 MAGQ 32024-2

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.