Days Set Up
Varies, Monday, Tuesday, Wednesday, Friday
Analytic Time

7 - 12 days

Soft Order Code

Test Updated:


Phosphorus, Stool
Magnesium, Stool

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Test Overview

Test Methodology

Inductively Coupled Plasma Optical Emission Spectrometry (ICP/OES)

Test Usage

Compliance or Abuse Monitoring of Laxatives

Reference Range

MAGNESIUM: Magnesium concentrations in stool water above the normal levels of 0.7 - 1.2 mg/mL have been indicative of surreptitious abuse of magnesium containing laxatives. NMS Labs Calculated Normal: approximately 0.5 - 10 mg/g. PHOSPHORUS: Phosphorus concentration in stool water averaged 1.8 +/- 0.3 mg/mL (ranged from 0.3 - 4.2 mg/mL) following administration of 105 mmol of sodium phosphate. NMS Labs calculated normal: approximately 1.4 - 22 mg/g.

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

Specimen Requirements

Collection Onsite

Collect random stool specimen.

Collection Offsite

Collect random stool specimen and refrigerate.

Normal Volume
10 grams (solid) or 10 mL (fluid) stool
Minimum Volume

Billing Information

CPT Code
80103 x2, 83735, 84100
Pro Fee Code

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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.