The Usefulness of Clinical-Practice-Based Laboratory Data in Facilitating the Diagnosis of Dengue Illness

Table 4

Sensitivity, specificity, PPV, NPV, accuracy, and AUC of laboratory variables included in ROC curve analysis¹.

Laboratory parameter	Overall dengue						DF						DHF
	Sn (%)	Sp (%)	PPV (%)	NPV (%)	Ac (%)	AUC (95% CI)	Sn (%)	Sp (%)	PPV (%)	NPV (%)	Ac (%)	AUC (95% CI)	Sn (%)	Sp (%)	PPV (%)	NPV (%)	Ac (%)	AUC (95% CI)
PC < 100×10^9 cells/L	97.0	70.0	76.4	95.9	83.5	0.835 (0.775–0.895)	94.7	70.0	64.3	95.9	79.0	0.824 (0.751–0.890)	100	70	58.9	100	79.0	0.850 (0.789–0.911)
Prolonged APTT + normal PT + PC < 100×10^9 cells/L	87.9	78.9	87.9	78.9	84.6	0.834 (0.746–0.923)	88.9	78.9	80.0	88.2	83.8	0.839 (0.742–0.936)	86.7	78.9	76.5	88.2	82.4	0.828 (0.724–0.932)
PC < 100×10^9 cells/L + ALT > 40 U/L						0.747						0.699	89.3	75.5	65.8	93	80.2	0.852 (0.761–0.943)
PC < 100×10^9 cells/L + ALT > 40 U/L + AST > 40 U/L						0.766						0.701	92.6	76.6	69.4	94.7	82.4	0.846 (0.752–0.939)
Prolonged APTT + normal PT + AST > 40 U/L						0.791						0.781	88.5	75.0	76.7	87.5	81.5	0.817 (0.698–0.937)
Prolonged APTT + normal PT + ALT > 40 U/L						0.765						0.729	81.0	81.5	77.3	84.6	81.3	0.812 (0.682–0.942)

Abbreviations: Sn: sensitivity; Sp: specificity; PPV: positive predictive value; NPV: negative predictive value; Ac: accuracy; AUC: area under the receiver-operator characteristic curves; DF: dengue fever; DHF: dengue hemorrhagic fever; CI: confidence interval; PC: platelet count; APTT: activated partial thromboplastin time; PT: prothrombin time; AST: aspartate aminotransferase; ALT: alanine aminotransferase.
¹Only sensitivity, specificity, positive predictive value, and negative predictive value of variables having an accuracy with an AUC > 0.8 (in bold font) in ROC analysis are shown. Calculations of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were based on formulae put in the footnote of Table 3.