Urine specific gravity measurements: comparison of a new reagent strip method with existing methodologies, as applied to the water concentration/dilution tests.

A study was carried out to compare a new, unique chemical strip test for the measurement of urine specific gravity with the traditional methods of hydrometry and refractometry, during water concentration/dilution tests in 12 normal subjects. The pattern of specific gravity results during these serial measurements was virtually identical for the strip and for the comparative methods. Comparison of the strip results with those obtained by both hydrometry and refractometry produced acceptable linear regression data. In addition, a close relationship was demonstrated between the strip specific gravity and urine osmolality. The findings show that the strip method is an acceptable alternative to traditional methods as an indicator of urine concentration.