Table 6.

Accuracy of the combination of D-dimer and ESR in predicting persistent 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 (+)	7	27	34
D-dimer and ESR (-)	3	6	9
Total	10	33	43
Accuracy = 100 x 3 + 27/3 + 27 + 7 + 6 = 70% Sensitivity = 100 x 3/3 + 7 = 30% Specificity = 100 x 27/27 + 6 = 82% Positive predictive value = 100 x 3/3 + 6 = 33% Negative predictive value = 100 x 27/27 + 7 = 79% Positive likelihood ratio = 0.3/1-0.818 = 1.6 Negative likelihood ratio = 1-0.3/0.818 = 0.8