Detection of membrane neutrophilic alkaline phosphatase by flow cytometry in diagnosis of ;bloodstream infection / 中华临床感染病杂志

ABSTRACT

Objective To evaluate the detection of membrane neutrophilic alkaline phosphatase ( mNAP) by flow cytometry in diagnosis of bloodstream infection .Methods A total of 298 patients with suspected bloodstream infections admitted in the First People ’ s Hospital of Lianyungang during June 2013 and October 2014 were enrolled;80 healthy subjects in physical examination center were also enrolled as the control group.Bloodstream infection was diagnosed by blood culture and mNAP was detected by flow cytometry.Serum levels of procalcitonin (PCT) and C-reactive protein (CRP) were detected by electro-chemiluminescence (ECL) and immune scatter turbidimetry , respectively.The value of mNAP, PCT and CRP in diagnosing bloodstream infection was determined by receiver operating characteristic ( ROC) curve. Results Among 298 patients, 109 were confirmed with bloodstream infections , including 43 patients with Gram-positive bacterial infections and 66 with Gram-negative bacterial infections .The median levels of CRP , PCT and mNAP in bloodstream infection group were 138.71 mg/L, 7.04 ng/mL and 13 929 AB/c, which were significantly higher than those in healthy control group (1.50 mg/L, 0.12 ng/mL, 1 831 AB/c;U=5.00, 48.50 and 65.01, P<0.01).The expression of mNAP in Gram-positive bacterial infection group was 9 598 ( 6 064-11 643 ) AB/c, which was significantly lower than that in Gram-negative bacterial infection group [16 512 (11 654-22 001) AB/c] (U=250.00, P<0.01).ROC curve analysis showed that, the areas under the curve (AUCs) of mNAP, PCT and CRP in diagnosing bloodstream infection were 0.987, 0.962 and 0.901.When 4 578AB/c, 0.90 ng/mL and 13.50mg/L were taken as optimal cut-off values, the sensitivities of mNAP, PCT and CRP in diagnosis of bloodstream infection were 95.8%, 93.0%and 90.3%; the specificities were 97.8%, 95.6% and 85.5%, respectively.Conclusion Among mNAP, PCT and CRP, mNAP is of the highest value in diagnosing bloodstream infection , and may be used as a biomarker for clinical diagnosis of bloodstream infection .