Validity of Urine Color Scoring Using Different Light Conditions and Scoring Techniques to Assess Urine Concentration

Abstract

Context: Urine color (Uc) is used to asses urine concentration when laboratory techniques are not feasible. Objective: To compare the accuracy of Uc scoring using 4 light conditions and 2 scoring techniques with a 7-color Uc chart. Additionally, to assess the results' generalizability, a subsample was compared with scores obtained from fresh samples. Design: Descriptive laboratory study. Samples: A total of 178 previously frozen urine samples were scored, and 78 samples were compared with their own fresh outcomes. Main Outcome Measure(s): Urine color and accuracy for classifying urine samples were calculated using receiver operating characteristics analysis, allowing us to compare the diagnostic capacity against a 1.020 urine specific gravity cutoff and defining optimal Uc cutoff value. Results: Urine color was different among light conditions (P