Table 1

Summary of studies quantifying the diagnostic performance of clinical signs of dehydration and/or investigating their predictivity of dehydration severity

Author	Study setting	Inclusion criteria	Exclusion criteria	Sample size	Key results
Caruggi et al	2 children’s EDs (Italy)	Children aged 9 months–17 years with acute gastroenteritis	Newborn babies (correct age <1 month), children on tube feeding or with chronic poor health (listed)	242	Significant correlation between CRT and dehydration. CDS correlated with percentage dehydration and length of stay.
Falszewska et al	1 children’s ED (Poland)	Children aged 1 month–5 years with acute gastroenteritis	Other causes of dehydration (listed)	128 children	CDS unable to rule out dehydration but was able to predict severity
Gorelick et al	1 urban ED (USA)	Children aged 1 month to 5 years with acute gastroenteritis	Symptoms longer than 5 day-duration, history of chronic disease (listed) 12 hours at another health facility and hyponatremia or hypernatremia.	186 children	All these parameters were significantly associated with the presence of dehydration: Decreased skin elasticity: PPV 0.57, NPV 0.93, sensitivity 0.35, specificity 0.97. CRT>2 s: PPV 0.57, NPV 0.94, sensitivity 0.48, specificity 0.96. Ill general appearance: PPV 0.42, NPV 0.95, sensitivity 0.59, specificity 0.91. Absent tears: PPV 0.40, NPV 0.96, sensitivity 0.67, specificity 0.89. Abnormal respiration pattern: PPV 0.37, NPV 0.94, sensitivity 0.43, specificity 0.86. Dry mucous membranes: PPV 0.29, NPV 0.99, sensitivity 0.80, specificity 0.78. Sunken eyes PPV 0.29, NPV 0.95, sensitivity 0.60, specificity 0.84. Abnormal radial pulse: PPV 0.25, NPV 0.93, sensitivity 0.43, specificity 0.86. Tachycardia PPV 0.20, NPV 0.93, sensitivity 0.46, specificity 0.79. Decreased urine output: PPV 0.17, NPV 0.97, sensitivity 0.85, specificity 0.53.
Mackenzie et al	1 children’s hospital (Australia)	Children under 4 years admitted with gastroenteritis	Less than 5% dehydration	102 children	Signs of dehydration of >4% Deep breathing (PPV 0.58, p=0.023). Decreased peripheral perfusion (PPV 0.65, p=0.024). Decreased skin turgor (PPV 0.52, p=0.056).
Hoxha et al	1 urban hospital (Kosovo)	Children aged 1 month–5 years admitted with gastroenteritis		200 children	The number of episodes of diarrhoea correlate with the degree of dehydration (p=0.004).
Friedman et al	1 tertiary children’s ED (Canada)	Children between 1 and 36 months of age with gastroenteritis	Any cause of dehydration chronic disease	141 children	General ill appearance, sunken eyes, dry mucous membranes and absent tears were significantly associated with the degree of dehydration: Pearson’s correlation coefficients were 0.66, 0.62, 0.74 and 0.74, respectively.
Steiner et al	Meta-analysis	26 studies in young children aged 1 month–5 years	13 excluded due to the lack of an accepted diagnostic standard or other limitation in study design	1246 children	Three signs had a clinically helpful pooled LR in detecting 5% dehydration: Prolonged CRT: LR 4.1 (95% CI 1.7 to 9.8). Abnormal skin turgor had a pooled LR of 2.5 (95% CI 1.5 to 4.2). Abnormal respiratory pattern: LR of 2.0 (95% CI 1.5 to 2.7). Low urine output did not increase the likelihood of 5% dehydration (LR, 1.3; 95% CI, 0.9 to 1.9).

CDS summarised in table 2.
CDS, Clinical Dehydration Score; CRT, capillary refill time; ED, emergency department; LR, likelihood ratio; NPV, negative predictive value; PPV, positive predictive value.