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

Table 2 Diagnostic performance of biomarkers individually

Biomarker	AUC (95% CI)	Youden index	Cut-off	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)
CRP (mg/L)	–	0.598	10.00*	82.4	77.4	80.0	80.0
CRP (mg/L)	0.845 (0.744–0.947)	0.656	8.40^#	88.2	77.4	81.1	85.7
ESR (mm/h)	–	0.501	30.00*	82.4	67.7	73.7	77.8
ESR (mm/h)	0.820 (0.715–0.925)	0.566	33.00^#	82.4	74.2	77.8	79.4
D-dimer (mg/L)	0.595 (0.429–0.860)	0.335	0.80	85.7	47.8	66.7	73.3
FDP (mg/L)	0.550 (0.366–0.733)	0.094	2.80	56.5	52.9	61.9	47.3
IL-6 (pg/L)	0.839 (0.724–0.953)	0.529	6.00	83.3	69.6	74.1	80.0

AUC, area under the receiver operating characteristic curve; CI, confidence interval; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; FDP, fibrin degradation product; IL-6, interleukin-6; PPV, positive predictive value; NPV, negative predictive value
^*From the 2013 International Consensus Meeting Criteria on PJI [23]
^#Based on the Youden index for our cohort

ISSN: 1749-799X