A comparison of reagent strips and the refractometer for measurement of urine specific gravity in hospitalized children.

Pediatric nurses in acute care settings routinely test urine for specific gravity, pH, glucose, protein, and other substances. In one tertiary care facility, nurses used the refractometer to test urine specific gravity and the reagent strip to test for other substances. This study was designed to provide data to determine if the reagent strip and the refractometer were interchangeable for measuring urine specific gravity in pediatric clients. Nurses obtained urine for specific gravity testing in 157 pediatric patients ranging in age from 1 day to 16 years. Each urine specimen was tested twice, once using the refractometer and once with the reagent strip. A Bland-Altman plot was used to determine the extent of agreement between the two measurement methods. The plot showed strong agreement between the two methods across a wide range of values for urine specific gravity. As a result of this study, staff nurses decided to use the reagent strip for urine specific gravity when other urine tests are needed and to use the refractometer when only a specific gravity is needed. This decision has resulted in a time savings for nurses who now do not have to repeat a reagent strip measurement. The decision also resulted in a savings of approximately $1200 in purchase of new refractometers for a newly constructed unit.