Diagnostic accuracy of C-reactive protein for periprosthetic joint infection: a meta-analysis

We conducted a study to assess the diagnostic accuracy of the C-reactive protein (CRP) assay for periprosthetic joint infection (PJI).

For the purpose of the study, we conducted a search of PubMed, selecting only studies that described the diagnosis of PJI through measurement of the serum CRP concentration. The results were meta-analyzed by pooling estimates of sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), and diagnostic odds ratio (DOR) and constructing respective summary receiver-operating characteristic (SROC) curves. We also conducted subgroup analyses according to cutoff values of the serum CTP concentration.

A total of 25 studies met the selection criteria for inclusion in the analysis. The pooled estimates for sensitivity, specificity, and the area under the curve (AUC) for the CRP assay were 0.82 (95% CI 0.80-0.84), 0.77 (95% CI 0.76-0.78), and 0.877±0.016, respectively. In the 10 mg/L cutoff subgroup, the pooled estimates for sensitivity, specificity, and the AUC were 0.881 (95% CI 0.859-0.901), 0.728 (95% CI 0.706-0.749), and 0.8496±0.0248, respectively.

We found that the serum CRP assay had good diagnostic accuracy for PJI but that its specificity was low. We recommend that when the CRP assay yields a normal result, other tools be used adjunctively with it to reduce the rate of false-negative diagnoses of PJI.