Therefore, our purposes were to assess the reliability of refractometry, hydrometry, and reagent-strip measurements across multiple trials and testers and to investigate the validity of hydrometer and reagent-strip measurements compared with refractometry using a variety of statistical approaches. 20, 21 Furthermore, none of these authors assessed the reliability of refractometry, hydrometry, or reagent strips. 12, 16 вЂ“ 19 Although these findings are contradictory, the interclass Pearson correlation coefficients reported in these previous validity studies might not be the most appropriate statistical approach to use when comparing 2 methods of measurement. McCrossin and Roy 12 described the overall correlation between refractometry and hydrometry as вЂњgood.вЂќ In studies comparing refractometry with reagent strips, several researchers have suggested that reagent strips are an acceptable alternative to refractometry, 13 вЂ“ 15 whereas others have concluded that they are not. Research to assess the validity of hydrometry and reagent strips compared with refractometry to determine urine specific gravity has provided mixed results. Finally, the recent National Athletic Trainers' Association position statement on fluid replacement for athletes stated that urine specific gravity measured by a refractometer should be used to determine the hydration status of athletes. Popowski et al 11 also concluded that measurement of urine specific gravity by refractometry was a valid assessment of hydration status, although it may lag somewhat behind plasma osmolality during progressive acute dehydration. 8 вЂ“ 11 In 2 papers assessing urinary indices of hydration status, Armstrong et al 8, 9 reported that urine specific-gravity measurement by refractometry was a more sensitive indication of hydration status than blood measurements, including plasma osmolality, plasma sodium, or hematocrit. 6 Previous reports have indicated that refractometry is the criterion measure for urine specific gravity 7 and that urine specific gravity measured by refractometry is a valid indication of hydration status. 4 However, in 1999, the use of reagent strips was eliminated. In 1998, the NCAA allowed the use of all 3 methods. Refractometry, hydrometry, and reagent strips are commonly used to assess urine specific gravity. 4 Wrestlers with a urine specific gravity в‰¤1.020 are considered euhydrated and may have their body composition assessed to determine their minimal weight for competition, whereas wrestlers with a urine specific gravity >1.020 are considered to be dehydrated and may not proceed to body-composition testing on that day.

5 The NCAA selected a urine specific-gravity measurement of в‰¤1.020 to indicate euhydration. Urine specific-gravity measurements normally range from 1.002 to 1.030. Urine specific gravity is a measure of the ratio of the density of urine to the density of water. The NCAA selected urine specific gravity as the most practical, cost-efficient hydration measure to use during the weight-certification process. 1 вЂ“ 3 These new rules include a weight-certification process that requires the determination of hydration status. 1 вЂ“ 3 To prevent a recurrence of this tragedy, the National Collegiate Athletic Association (NCAA) introduced new rules in 1998 that discourage dangerous weight-cutting practices. In 1997, three collegiate wrestlers died while attempting to reduce weight by dehydration.

Normal specific gravity lab values