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Urine Reagent Strips Are Inaccurate for Assessing Hypohydration

A Brief Report

Adams, J.D. PhD*; Capitan-Jiménez, Catalina MS; Huggins, Robert A. PhD; Casa, Douglas J. PhD; Mauromoustakos, Andy PhD§; Kavouras, Stavros A. PhD*,¶

Clinical Journal of Sport Medicine: November 2019 - Volume 29 - Issue 6 - p 506–508
doi: 10.1097/JSM.0000000000000555
Brief Report

Objective: 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.

*Hydration Science Lab, University of Arkansas, Fayetteville, Arkansas;

Department of Nutrition, Universidad Hispanoamericana, San José, Costa Rica;

Korey Stringer Institute, University of Connecticut, Storrs, Connecticut;

§Department of Crop, Soil, and Environmental Sciences, Agricultural Statistics Laboratory, University of Arkansas, Fayetteville, Arkansas; and

Division of Endocrinology, University of Arkansas for Medical Sciences, Little Rock, Arkansas.

Corresponding Author: Stavros A. Kavouras, PhD, Hydration Science Lab, University of Arkansas, 155 Stadium Dr., Fayetteville, AR 72701 (

D. J. Casa during the past 24 months had grants with Mission, Welkins, General Electric, Quest, CamelBak, NFL, Kestrel, One Beat, Gatorade, Danone, Timex, UNC [Preventing sudden death in sport, heat stroke, thermoregulation, hydration (Cooling products, hydration products, and wearable technology)]. D. J. Casa, S. A. Kavouras, and R. A. Huggins were scientific consultants for Quest Diagnostics during the past 24 months. S. A. Kavouras has active grants with Danone Research.

The remaining authors report no conflicts of interest.

Received June 22, 2017

Accepted October 31, 2017

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