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Test Code UOSM or LAB420 Osmolality, Urine

Specimen Requirements

Container Type:

Sterile urine cup

 

*Urine may be random or timed. If the urine is from a timed collection, indicate the start and end times on the container.

Optimal Collection Volume: 

5 mL

Minimum Volume:

1 mL

Collection Instructions:

1. Collect a random urine specimen from the patient.

2. Ensure the lid is secured tightly before sending it to the lab.

3. Ensure that no preservatives are used.

Specimen Transport:

Refrigerate

Processing Instructions: 

1. Pour off urine into a labeled aliquot tube.

2. Centrifuge the urine aliquot.

3. Deliver the urine aliquot to the chemistry department.

Specimen Stability

Specimen Type Temperature Time
Urine Refrigerated 7 days
Room Temperature 36 hours
Frozen 30 days

Specimen Rejection Criteria

Quantity not sufficient

Useful For

Assessing the kidney's ability to maintain both tonicity and water balance of extracellular fluid. 

Methodology

Advanced Osmometer Model 3320 - Freeze point depression

Reference Ranges

300-1100 mOsm/kg

Day(s) Performed

24/7

Expected TAT

Same day

Performing Laboratory

Bronson Laboratory, Chemistry - Kalamazoo and Battle Creek

Sample Retention Time

7 days

CPT Code

83935

LOINC Code

2695-5