. 2019 Oct 30;9(10):e025336. doi: 10.1136/bmjopen-2018-025336

Table 5.

Combination of diagnostic indicators and ROC analysis results*

Indicators	AUC (95% CI)	Sensitivity, %	Specificity, %	Predict⁺, %	Predict⁻, %	P value
Tryptophan	0.67 (0.57 to 0.77)	69.64	62.50	65.00	67.31	0.002
Phenylalanine	0.70 (0.60 to 0.80)	69.64	69.64	69.64	69.64	0.002
Combined†	0.72 (0.62 to 0.81)	76.79	58.93	65.15	71.74	<0.001

*The sensitivities, specificity, positive predictive value and negative predictive value were calculated at their best cut-off points; Predict+: positive predictive value; Predict−: negative predictive value.

†Combined: tryptophan and phenylalanine. The combination is modelled according to the formula β₁X₁ + β₂X₂, with X_j denoting the standardised value for the j^th amino acid and βj denoting the regression coefficient from the logistic regression model.

AUC, area under the curve; ROC, receiver operator characteristic.