Test Overview

Test Methodology

Freezing Point

Test Usage

To aid in evaluation of water balance and kidney function.

Reference Range*

300 - 1300 mOsm/kg for random specimens

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

Test Details

Days Test Performed

Daily, 24 hours

Analytic Time

2 hours

Soft Order Code


MiChart Code

Osmolality, Urine




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Chemical Pathology

STAT Availability

STAT requests for this test will be performed on a STAT basis (supervisory staff approval is not required).

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Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

Learn about how to properly label and where to ship specimens.

Order Kits and Supplies

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

Test FAQ

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Specimen Requirements

Offsite Collection Instructions

Collect 24 hour urine specimen with no preservative. Aliquot 2 mL into a plastic urine container and refrigerate. Record total 24 hour urine volume and collection dates/times on request form. Random urine is also acceptable.

Rejection Criteria

Specimens collected with Acid Preservative are not acceptable.

Normal Volume

2 mL aliquot of random or 24 hour urine collection

Minimum Volume

0.5 mL aliquot of random or 24 hour urine collection

Billing Information

Fee Codes

CPT Code




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