Selection process
Initially, 611, 468 and 276 articles were retrieved from PubMed, Web of Science Core Collection and EMBASE respectively. Secondly, 332 duplicates were removed. Thirdly, the titles and abstracts of the remaining 1023 articles were examined and 975 articles were excluded for diverse reasons. Finally, 11 articles were selected after the full text review and 1 article[33] was added by reviewing references. The process and outcome of the literature selection are presented in detail in Figure 1.
Risk of bias and applicability concerns in included studies
Figure 2 and Figure 3 showed the risk of bias and applicability concerns in different domains. Among these 12 included articles, 4 had a high risk of bias on “flow and timing”, “patient selection”, “index test”, and “reference standard”, indicting the quality Methodological quality of included studies was moderate. Eight out of twelve studies had low applicability concerns in all domains and the applicability concerns was low.
Characteristics of selected studies
Twelve included studies were published from 2010 to 2018. All these studies applied the tympanic thermometer and set the rectal thermometer as reference standard. The descriptive and statistical characteristics of the 12 studies were presented in Table 1 and Table 2 respectively.
Accuracy of Tympanic Thermometry in children under different cut-offs
The 12 studies involved 4639 children. The cut-off points were various. Among the included articles, 7[5, 8, 18, 33-36] studies set the optimal cut-off and the other 5[3, 13, 14, 20, 21] studies analyzed the diagnostic test accuracy of tympanic thermometry under different cut-offs. The range of the cut-off point was from 37.0℃ to 38.0℃. Studies had data under same cut-off were synthesized.
Accuracy under the cut-off of 37.0℃
There was only one study[3] reported diagnostic test accuracy under the cut-off 37.0℃. In this study, for ear temperature (37.0°C), sensitivity, specificity, PPV, and NPV were 0.89, 0.84, 0.91, and 0.81 respectively
Accuracy under the cut-off of 37.25℃
Only one study[34] gave the optimal cut-off 37.25℃ and sensitivity, specificity, PPV, and NPV were 0.83, 0.86, 0.88, and 0.80 respectively.
Accuracy under the cut-off of 37.4℃
There was only one study[20] reported diagnostic test accuracy under the cut-off 37.4℃. In this study, for ear temperature (37.4°C), sensitivity, specificity, PPV, and NPV were 0.96, 0.36, 0.82, and 0.73 respectively.
Accuracy under the cut-off of 37.5℃
The cut-off 37.5℃ was used in 2 studies[20, 35] and a total of 390 pediatric patients were involved. The pooled sensitivity was 0.87 (95% CI 0.79-0.92) and heterogeneity between the articles was high: 87.5% (X2=8.02, P<0.05). The pooled specificity was 0.95 (95% CI 0.92-0.97) and heterogeneity between the articles was high: 97.9% (X2=47.74, P<0.05).
Accuracy under the cut-off of 37.6℃
The cut-off 37.6℃ was used in 4 studies[3, 13, 20, 21] and a total of 746 pediatric patients were involved. Spearman’s correlation coefficient of sensitivity and specificity was 0.089 (P = .638) and the ROC plane showed no curvilinear trend, suggesting that there was no heterogeneity from threshold effect. The pooled sensitivity was 0.76 (95% CI 0.71-0.80) and heterogeneity between the articles was high: 94.3% (X2=53.04, P<0.05). The pooled specificity was 0.88 (95% CI 0.84-0.91) and heterogeneity between the articles was high: 92.9% (X2=42.22, P<0.05) (Figure 5). The sROC AUC was 0.93 (SE = 0.02) while Q* value was 0.86 (SE=0.03).
Accuracy under the cut-off of 37.7℃
There was only one study[20] reported diagnostic test accuracy under the cut-off 37.7℃. In this study, for ear temperature (37.7℃), sensitivity, specificity, PPV, and NPV were 0.91, 0.60, 0.87, and 0.68 respectively.
Accuracy under the cut-off of 37.8℃
The cut-off 37.8℃ was used in 3 studies[14, 20, 21] and a total of 1795 pediatric patients were involved. The threshold analysis (r=-0.050 , P = .667) and the ROC plane (Figure) suggested that there was no heterogeneity from threshold effect. The pooled sensitivity was 0.92 (95% CI 0.90-0.94) and heterogeneity between the articles was high: 80.1% (X2=10.07, P<0.05). The pooled specificity was 0.91 (95% CI 0.89-0.92) and heterogeneity between the articles was high: 94.5% (X2=36.68, P<0.05) (Figure 6). The sROC AUC was 0.97 (SE = 0.02) while Q* value was 0.91 (SE=0.03).
Accuracy under the cut-off of 38.0℃
The cut-off 38.0℃ was used in 7 studies[5, 8, 13, 14, 18, 33, 36] and a total of 2783 pediatric patients were involved. The threshold analysis (r=0.429, P = 0.337) and the ROC plane suggested that there was no heterogeneity from threshold effect. The pooled sensitivity was 0.81 (95% CI 0.79-0.84) and heterogeneity between the articles was high: 93.7% (X2=94.51, P<0.05). The pooled specificity was 0.96 (95% CI 0.95-0.97) and heterogeneity between the articles was high: 81.6% (X2=32.56, P<0.05). The sROC AUC was 0.97 (SE = 0.01) while Q* value was 0.92 (SE=0.01).
The diagnostic test accuracy of the tympanic thermometry under different Cut-offs in the detection of pediatric fever is summarized in Table 3. The cut-off 37.8 is with the highest sROC AUC and Youden Index and is deemed to be the optimal cutoff.