To assess the diagnostic ability of urine reagent strips to identify hypohydration based on urine specific gravity (USG).Design:
This study examined the agreement of USG between strips and refractometry with Bland–Altman, whereas the diagnostic ability of the strips to assess hypohydration was performed by receiver operating characteristic analysis.Setting:
Arkansas high school football preseason practice.Participants:
Four hundred fourteen fresh urine samples were analyzed.Main Outcome Measures:
Urine specific gravity was assessed by both reagent strips and refractometry. Cutoffs of >1.020 and >1.025 were used for identifying hypohydration.Results:
Bland–Altman analysis showed agreement of the 2 methods. Overall diagnostic ability of the urine strip to identify hypohydration was fair (area under the curve 72%-78%). However, the sensitivity to correctly identify hypohydration was poor (63%-71%), and the specificity of correctly identifying euhydration was poor to fair (68%-83%).Conclusion:
The urine strip method is not valid for assessing hypohydration.