[Evaluation of a method for determining the specific gravity of urine with a reagent strip]

The performance of a new reagent strip method for determining the urine specific gravity was evaluated. 342 clinical specimens were assayed in duplicate by the new method and by the "falling drop" technique. The reproducibility (two lots of strips, four operators) was very good (96.2 per cent agreement between replicates within a range of 0,0100 specific gravity units). The correlation with the comparative method was satisfactory [81,2 per cent concordance within a range of 0,0100 specific gravity units]. No interference was found from ketones, blood or urobilinogen. The influence of proteins and glucose is discussed. The practical advantages of the new method are described.