Association between urine osmolality and specific gravity in dogs and the effect of commonly measured urine solutes on that association.

Abstract

OBJECTIVE:

To determine the association between urine osmolality and specific gravity (USG) in dogs and to evaluate the effect of commonly measured urine solutes on that association.

ANIMALS:

60 dogs evaluated by an internal medicine service.

PROCEDURES:

From each dog, urine was obtained by cystocentesis and USG was determined with a refractometer. The sample was divided, and one aliquot was sent to a diagnostic laboratory for urinalysis and the other was frozen at -80°C until osmolality was determined. Urine samples were thawed and osmolality was measured in duplicate with a freezing-point depression osmometer. The correlation between mean urine osmolality and USG was determined; the effect of pH, proteinuria, glucosuria, ketonuria, bilirubinuria, and hemoglobinuria on this relationship was investigated with multiple regression analysis.

RESULTS:

The Pearson correlation coefficient between urine osmolality and USG was 0.87. The final multivariable regression model for urine osmolality included USG and the presence of ketones; ketonuria had a small negative association with urine osmolality.

CONCLUSIONS AND CLINICAL RELEVANCE:

Results indicated a strong linear correlation between osmolality and USG in urine samples obtained from dogs with various pathological conditions, and ketonuria had a small negative effect on that correlation.

• Authors: Jennifer A Ayoub, Hugues Beaufrere, Mark J Acierno
• Journal: American journal of veterinary research (Am J Vet Res) Vol. 74 Issue 12 Pg. 1542-5 (Dec 2013) ISSN: 1943-5681 [Electronic] United States
• PMID: 24274893 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Bilirubin

Topics

• Animals
• Bilirubin (urine)
• Dogs (urine)
• Glycosuria (urine, veterinary)
• Hemoglobinuria (urine, veterinary)
• Hydrogen-Ion Concentration
• Ketosis (urine, veterinary)
• Osmolar Concentration
• Proteinuria (urine, veterinary)
• Refractometry (veterinary)
• Regression Analysis
• Specific Gravity
• Urinalysis (veterinary)
• Urine (chemistry)