P1217VALUE OF MYCOBACTERIUM TUBERCULOSIS SPECIFY ELISOPT IN THE DIAGNOSIS OF PERITONEAL DIALYSIS-ASSOCIATED TUBERCULOUS PERITONITIS PATIENTS

Abstract

Abstract Background and Aims Patients with ESRD undergoing chronic dialysis are 6 to 25 times more likely to develop tuberculosis (TB) than the general population. Tuberculous peritonitis is the most common form of tuberculosis infection in peritoneal dialysis patients. However, diagnosing active TB infection can be challenging, early and rapid diagnosis of tuberculous peritonitis has always been a challenge for nephrologists. M.tuberculosis antigen-specific IFN-γ production by peripheral blood mononuclear cells (PBMC) was determined by using an in-house ELISPOT assay by Institute of Hepatology of Shenzhen Third Hospital.In this study, we evaluated diagnostic performance of an M.tuberculosis antigen-specific gamma interferon enzyme-linked immunospot (ELISPOT) assay in continuous ambulatory peritoneal dialysis (CAPD) patients with tuberculous peritonitis. Method There were nine patients (1.29%) with tuberculous peritonitis among 700 CAPD patients. M. tuberculosis accounted for 2.84 % of all peritonitis.IFN-γ response in peripheral blood and peritoneal fluid were determined in 9 patients with tuberculous peritonitis(TBP),at the same time, 13 cases diagnosed with non-tuberculous peritonitis(NTBP) were enrolled.All patients were examined for tuberculosis-specific IFN-γ ELISPOT in peripheral blood and peritoneal dialysis fluid. Results 22 patients were recruited into this study, 9 were classified with confirmed tuberculosis peritonitis, 13 patients with bacterial or fungal peritonitis were enrolled as controls during the same period, in this patients, 3 were caused by Gram positive bacteria, 3 were caused by Gram negative bacteria, 3 were caused by fungus, 4 patients were negative athogenic bacteria culture .The AUC of ROC curve was 0.927 (95%CI:0.816–1.000,P=0.001) for ELISPOT on PFMC, which was higher than that of ELISPOT on PBMC (0.825,95%CI: 0.6490–1.000,P=0.011).When the cutoff value for the diagnosis of TBP was 40.5 SFCs/2 × 105 for ELISPOT on PBMC, with a sensitivity of 55.6%, a specificity of 92.3%,a diagnostic efficiency of 77.3%,The positive predictive value was83.3%, with negative predictive value of 75%,positive likelihood ratio of 7.2, and negative likelihood ratio of 0.48.The sensitivity, specificity,diagnostic efficiency,PPV, NPV, LR+, and LR- of the ELISPOT assay for the diagnosis of active TBP when performed on the PFMC were 77.8%, 84.6%, 81.8%, 77.8%, 84.6%, 5.05 and 0.26, respectively.Receiver operating characteristic(ROC) curves were used to estimate the diagnostic values of Elispot on PFMC and PBMC in 22 patients with confirmed TBP or NTBP. Conclusion IFN-γ release test can be used for early diagnosis of CAPD-related TBP; compared with peripheral blood, peritoneal dialysate may be a more effective and accurate way to diagnose CAPD complicated with tuberculous peritonitis.