Table 8.

Accuracy of the combination of D-dimer, ESR, and CRP in predicting the persistence of infection after reimplantation in two-stage exchange arthroplasty at a minimum 1-year follow-up

Test combination	Infection persistence	No infection persistence	Total
D-dimer and ESR and CRP (+)	8	30	38
D-dimer and ESR and CRP (-)	2	3	5
Total	10	33	43
Accuracy = 100 x 2 + 30/2 + 30 + 8 + 3 = 74% Sensitivity = 100 x 2/2 + 8 = 20% Specificity = 100 x 30/30 + 3 = 91% Positive predictive value = 100 x 2/2 + 3 = 40% Negative predictive value = 100 x 30/30 + 8 = 79% Positive likelihood ratio = 0.2/1-0.909 = 2.2 Negative likelihood ratio = 1-0.2/0.909 = 0.9