Days Set Up
Analytic Time

8 hours

MiChart Code
Phosphorus, 24 HR Urine
Soft Order Code

Test Updated:


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Test Overview

Test Methodology


Test Usage

Renal function test, evaluate calcium/phosphorus balance. Normal phosphate excretion reflects the dietary intake of phosphate. The excretion varies with growth, dietary intake, renal function, muscle mass and hormonal activity. Urinary phosphate excretion will be decreased in hyperthyroidism.

Reference Range

400 - 1200 mg/TV (24 hour collection). Random urine collections vary with dietary intake and are dependent on diurnal variation, and 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 or random sample. Instruct the patient to void at 8:00am and discard the specimen. Then collect all urine including the final specimen voided at the end of the 24 hour collection period, i.e., 8:00am the next morning. Refrigerate during collection. Screw the lid on securely. Container MUST be labeled with date and time collection started and finished. Transport the specimen promptly to the laboratory.

Collection Offsite

Collect 24 hour urine specimen with no preservative. Aliquot 5 mL into a plastic urine container 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
PHOSU 2778-9 PHOSQ 2779-7

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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.