Lab Test

Specific Gravity, Urine

Test Codes

EPIC: LAB5917, SGUR

Specimen Collection Criteria

Collect: A random, clean-catch, midstream urine specimen in a screw-capped container (preferred) or other sterile collection container. (Minimum: 1.0 mL)

Physician Office/Draw Specimen Preparation

Maintain specimen refrigerated (2-8°C or 36-46°F) and transport to the Laboratory.

Preparation for Courier Transport

Transport: Urine specimen, refrigerated (2-8 °C or 36-46 °F). (Minimum: 1.0 mL)

Rejection Criteria

Urine volume less than 1.0 mL.

Specimens not collected and processed as indicated.

In-Lab Processing

Deliver the specimen immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Canton Laboratory
Dearborn Chemistry Laboratory
Farmington Hills Hematology/Urinalysis Laboratory
Grosse Pointe Hematology/Urinalysis Laboratory
Royal Oak Urinalysis Laboratory
Troy Hematology/Urinalysis Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Wayne Chemistry Laboratory 

Performed

Sunday – Saturday.
Results available within 24 hours.

Reference Range

1.005 - 1.030.

Interpretation

Specific gravity is the ratio of the mass of solution compared to the mass of an equal volume of water. Therefore, it is a measure of the total solute concentration of urine when compared to water (1.000).

Random urine specimens can vary in specific gravity from 1.003 to 1.040+. Normal adults with normal diets and normal fluid intake will produce urine of specific gravity 1.016-1.022 during a 24 hour period. If a random urine has a specific gravity of greater than or equal to 1.023, concentrating ability can be considered normal.

Specific gravity values by refractometer less than 1.035 may be due to high concentrations of glucose or protein, but may also be due to presence of X-ray crystals or certain antibiotics. X-ray crystals can be assessed with microscopic analysis of the urinary sediment and a medication /X-ray contrast material history for the patient.

Clinical Utility

Low specific gravity (hyposthenuria) may indicate the loss of the kidney’s ability to concentrate urine, as can occur with renal diseases such as pyelonephritis, glomerulonephritis, and diabetes insipidis. A highly concentrated urine (hypersthenuria) may occur with congestive heart failure, Addison’s disease, cirrhosis, and forms of dehydration (vomiting, diarrhea, fever, heavy exercise).

CPT Codes

81003
LOINC: 50562-8, 5811-5

Contacts

Last Updated

7/1/2021

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