Urine reagent strips are inaccurate for
assessing hypohydration: A brief report
Adams JD,
Captain-Jimenez C, Huggins RA, Casa DJ, Mauromoustakos A, and Kavouras SA. Clin
J Sport Med
. [Epub Ahead of Print]. 2018.
Take Home Message: Reagent strips are not very accurate at detecting a
person with hypohydration.

Assessing athlete hydration
is an important part of ensuring athlete safety, especially in weight-dependent
sports such as wrestling. While refractometry is the gold standard, reagent
strips are also commonly available as an alternative. To date, no one has directly
compared the diagnostic ability of reagent strips to diagnose hypohydration
compared to refractometry. Therefore, Adams and colleagues completed a study to
investigate the validity of reagent strips to diagnose hypohydration. A total
of 414 urine samples from healthy adults and high school football players were
obtained as part of a larger study and analyzed using both reagent strips and
refractometry. All testing was performed within 2 hours of urination.
Hypohydration cutoff was defined at 2 different levels (>1.020 and
>1.025) both of which are used by state high school organizations. Overall,
reagent strips showed low to moderate accuracy and had a high false positive
rate. Further, positive and negative likelihood ratios for the >1.020 and
>1.025 cutoff points were 1.2 and 1.1, and 0.83 and 0.77, respectively.

Overall, the current
study demonstrated that compared to the gold standard of refractometry, reagent
strips were not accurate enough in identifying hypohydration. This result
supports a recent decision by the NCAA to no longer allow reagent strips in
wrestling weight certification due to inaccuracies. Clinicians who work with
weight-dependent athletes, such as wrestlers, should use refractometry to
accurately and quickly assess an athlete’s hydration status. It is possible,
however, that more research regarding the accuracy of reagent strips in the
future could yield better results as technology improves. Until this time
though refractometry should remain as the primary method of assessing hydration.
Questions for Discussion: Have
you used reagent strips in your current clinical practice? What factors
attributed to your use of reagent strips and would you consider using only
refractometry after reading the current study?
Written by: Kyle Harris
Reviewed by: Jeffrey Driban
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