Does the use of parameters derived from complete blood count increase the accuracy of septic arthritis diagnosis in adult patients?

Abstract

The diagnosis of septic arthritis can be challenging and any delay in treatment can cause important disabilities. This study aimed to evaluate several ratios obtained from routine blood tests for possible use in the diagnosis of septic arthritis. Adult patients operated with the diagnosis of septic arthritis were retrospectively evaluated. 34 patients were found to be eligible for inclusion. The control group comprised 40 age-matched knee osteoarthritis patients without infection. Neutrophil-lymphocyte, monocyte-lymphocyte, platelet-lymphocyte, and platelet count-mean platelet volume ratios were calculated, and receiver operating characteristics (ROC) curve analysis was performed to determine the sensitivity, specificity, and area under curve (AUC) values of all parameters. Affected joints in the septic arthritis group included 22 knees, 6 hips, 4 shoulders, and 2 elbows. All evaluated parameters were significantly different between the groups (p<0.001). AUC value representing diagnostic performance was 97.3 when CRP and ESR values were used but increased to 98.6 when neutrophile/lymphocyte ratio was added and increased to 100 when all analyzed parameters were included. Analyzed parameters were found to increase the overall sensitivity and specificity of septic arthritis diagnosis when used together with CRP and ESR. Neutrophil/lymphocyte ratio was found as the most powerful predictor amongst the analyzed ratios and more significantly increased when joint culture was positive.