Validation of a urine color scale for assessment of urine osmolality in healthy children

Abstract

AimUrine color (UC) is a practical tool for hydration assessment. The technique has been validated in adults, but has not been tested in children.PurposeThe purpose of the study was to test the validity of the urine color scale in young, healthy boys and girls, as a marker of urine concentration, investigate its diagnostic ability of detecting hypohydration and examine the ability of children to self-assess UC.MethodsA total of 210 children participated (age: 8–14 years, body mass: 43.4 ± 12.6 kg, height: 1.49 ± 0.13 m, body fat: 25.2 ± 7.8 %). Data collection included: two single urine samples (first morning and before lunch) and 24-h sampling. Hydration status was assessed via urine osmolality (UOsmo) and UC via the eight-point color scale.ResultsMean UC was 3 ± 1 and UOsmo 686 ± 223 mmol kg−1. UC displayed a positive relationship as a predictor of UOsmo (R2: 0.45, P < 0.001). Based on the receiver operating curve, UC has good overall classification ability for the three samples (area under the curve 85–92 %), with good sensitivity (92–98 %) and specificity (55–68 %) for detecting hypohydration. The overall accuracy of the self-assessment of UC in the morning or the noon samples ranged from 67 to 78 %. Further threshold analysis indicated that the optimal self-assessed UC threshold for hypohydration was ≥4.ConclusionsThe classical eight-point urine color scale is a valid method to assess hydration in children of age 8–14 years, either by researchers or self-assessment.

Assessing Hydration in Children: From Science to Practice

“…Moreover, urine color measured on a 24-h, a first-morning, and a before-lunch spot urine sample of 2010 children was shown to have a good diagnostic ability with good sensitivity (92 to 98%) for detecting hypohydration (Uosm ≥ 800 mmol/kg). This study also reported that children were able to accurately self-assess the urine color in 67 and 74% of, the morning and the noon samples [13]. These data clearly support and expand the applicability of the urine color chart in children.…”

“…The latter clinical trial also reported that boys and girls of 8-14 years of age are able to accurately self-diagnose hypohydration based on their urine color [13]. The capability of the self-diagnosis is an important first step.…”

“…The urine color scale was introduced and validated as an applicable tool for hydration assessment in adults [12], and recently also in children [13]. The latter clinical trial also reported that boys and girls of 8-14 years of age are able to accurately self-diagnose hypohydration based on their urine color [13].…”

“…Despite this limitation, several strengths of the hydration self-assessment tool are recognized. The tool (artwork D1, figures 1, 2, 3) is based on the urine color chart, a validated scale to assess human hydration status [12,13]. Moreover, the tool is developed with children for children, demonstrating that the tool is actually understood without further instructions and found attractive by children.…”

“…Recently, urine color has also been tested as a hydration biomarker among children. Urine color displayed in a clinical trial a positive relationship with urine osmolality [13]. Moreover, urine color measured on a 24-h, a first-morning, and a before-lunch spot urine sample of 2010 children was shown to have a good diagnostic ability with good sensitivity (92 to 98%) for detecting hypohydration (Uosm ≥ 800 mmol/kg).…”