Figure 1.

Urine specimen handling scheme. Observer 1 performed 2 readings with each refractometer, the dual-scale and the single-scale refractometer. Observer 2 did one reading with each refractometer. The measurement of urine specific gravity (USG) from supernatant was only performed by observer 1 who did 2 readings with each refractometer. Urine protein concentration was measured in 56 of 85 samples in which determination of osmolality was performed. Repeated USG measurements after storage were performed by observer 1 (2 measurements with each refractometer). Osmolality after storage was measured in 94 samples. In 80 samples, osmolality of both fresh whole urine and of stored supernatant was determined. For all statistical analyses including USG, the first reading of observer 1 was used.