Combination of PCT, sNFI and dCHC for the diagnosis of ascites infection in cirrhotic patients

BACKGROUND: It is difficult to diagnose ascites infection early in cirrhotic patients. The present study was to create and evaluate a new bioscore combined with PCT, sNFI and dCHC in the diagnosis of ascites infection in cirrhotic patients. METHODS: Two hundred and fifty-nine consecutive patients were enrolled; of which 51 patients were culture-positive spontaneous bacterial peritonitis (culture-positive SBP) and 58 patients were culture-negative SBP. The efficacy of procalcitonin(PCT), c-reactive protein (CRP), white blood cell (WBC), mean fluorescence intensity of mature neutrophils(sNFI) and difference in hemoglobin concentration between newly formed and mature red blood cells(dCHC) for diagnosing ascites infection was examined. These parameters were used to create a scoring system. The scoring system was analyzed by logistic regression analysis to determine which parameters were statistically different between ascites infection and non-ascites infection patients. Receiver operating characteristic curve (ROC) was used to analyze the diagnostic ability of bioscore for ascites infection. RESULTS: In ROC analysis, the area under the curves (AUC) for PCT was 0.852 (95% CI 0.803–0.921, P < 0.001), dCHC 0.837 (95% CI 0.773–0.923, P < 0.001), CRP 0.669 (95% CI 0.610–0.732, P = 0.0624), sNFI 0.838 (95% CI 0.777–0.903, P < 0.001), and WBC 0.624 (95% CI 0.500–0.722, P = 0.0881). Multivariate analysis revealed PCT, dCHC and sNFI to be statistically significant. The combination of these three parameters in the bioscore had an AUC of 0.937 (95% CI 0.901–0.994, P < 0.001). A bioscore of ≥3.40 was considered to be statistically significant in making a positive diagnosis of ascites infection. In different groups of ascites infection, bioscore also shown a high diagnostic value of AUC was 0.947(95% CI 0.882–0.988, P < 0.001) and 0.929 (95% CI 0.869–0.974, P < 0.001) for culture-positive SBP and culture-negative SBP group respectively. CONCLUSION: The composite markers of combining PCT, dCHC and sNFI could be a valuable diagnostic score to early diagnose ascites infection in patients with cirrhosis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12879-018-3308-1) contains supplementary material, which is available to authorized users.