Plasma levels of D-dimer and fibrin degradation product are unreliable for diagnosing periprosthetic joint infection in patients undergoing re-revision arthroplasty

Table 3 Diagnostic performance of biomarkers in combination

Combination	AUC (95% CI)	Youden index	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)
Combination of two markers
CRP + ESR	0.867 (0.779–0.956)	0.630	82.4	80.6	82.3	80.7
CRP + IL-6	0.877 (0.769–0.984)	0.700	91.7	78.3	81.5	90.0
ESR + IL-6	0.893 (0.805–0.981)	0.658	87.5	78.3	80.8	85.75
Combination of three markers
CRP + ESR + IL-6	0.897 (0.811–0.982)	0.656	91.7	73.9	78.6	89.5

AUC, area under the receiver operating characteristic curve; CI, confidence interval; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; IL-6, interleukin-6; PPV, positive predictive value; NPV, negative predictive value

ISSN: 1749-799X