ABSTRACT
Objective To understand the diagnostic values of procalcitonin (PCT),C-reactive protein (CRP),erythrocyte sedimentation rate (ESR),white blood cell (WBC) and neutmphilic granulocyte ratio (NE％) in distinguishing concurrent bacterial infection from idiopathic inflammatory myopathy (ⅡM).Methods Clinical data and laboratory examinations of 118 ⅡM patients were collected.The ⅡM patients were assigned to the bacterial infection group (n=66) or the non-infection group (n=52).The levels of PCT,CRP,ESR,WBC and NE％ were compared by the Mann-Whitney U tests between the two groups and receiver operating characteristic curves were generated in order to evaluate the diagnostic value.Results The levels of PCT (0.06 ng/ml,0.03 ng/ml,U=2.637,P＜0.01);CRP (15.80 mg/L,4.40 mg/L,U=5.944,P＜0.01);ESR (43.50 mm/1 h,27.00 mm/1 h,U=2.266,P＜0.05);WBC (9.85×109/L,7.70×109/L,U=2.675,P＜0.01) and NE％ (80.70％,75.75％,U=2.344,P＜0.01) were significantly higher in the ⅡM patient group with concurrent infection than in the noninfection ⅡM patient group.CRP showed the highest diagnostic value with sensitivity,specificity,positive predictive value and negative predictive value of 72.7％,82.7％,84.2％ and 70.5％,respectively.Conclusion The inflammatory biomarkers PCT,CRP,ESR,WBC and NE％ offer diagnostic accuracy in detecting bacterial infection in ⅡM patients.Particularly,CRP is the most sensitive and specific biomarker indetecting bacterial infection in ⅡM patients.