Comparison of the diagnostic values of neutrophil CD-64, CRP and procalcitonin levels in patients with sepsis

Sepsis is a public health problem that requires early diagnosis and treatment and has a high mortality and morbidity rate. The definitive diagnosis is made by demonstrating bacterial growth in the blood culture. However, problems such as the results of blood cultures taking time and false negative results complicate the diagnosis and cause delay in treatment. Biomarkers that are widely used for early diagnosis are C-reactive protein (CRP) and procalcitonin (PCT). In this study, we aimed to evaluate the role and importance of neutrophil CD64 level, a new biomarker, in the diagnosis of sepsis, in addition to these commonly used biomarkers. The study included 77 patients in the pediatric age group, excluding the neonatal period, who applied to Çukurova University Faculty of Medicine, Balcalı Hospital, Department of Pediatrics between the years 2020-2022, with suspected sepsis. Peripheral blood samples sent from patients were prospectively evaluated. Blood samples taken from 25 healthy children who applied to the outpatient clinics were used as the control group. Blood cultures were studied using the BACTEC FX (Becton Dickinson) hemoculture device from the samples. Microorganisms were identified by Biomeriux VITEK 2 automated diagnosis system by inoculating the growing specimens on solid media. Of the biochemical tests, CRP level was determined quantitatively by immunonephelometric method, and PCT level was studied by electrochemiluminescence method. Determination of CD64 level was performed by flow cytometric method using NAVIOS, Beckman Coulter/France device and CD45 KO, CD64 APC A750 monoclonal antibodies. The sensitivity and selectivity of the neutrophil CD64 index in the diagnosis of sepsis were found to be 94.4% and 100%, the area under the curve was 0.981, youden's index was 0.986, and the p value was 0.001. The sensitivity for CRP was 93.5%, the specificity was 100%, the area under the curve was 0.978, and the youden index was 0.935, p value was 0.001. For PCT, the sensitivity was 90.9%, the selectivity was 92%, the area under the curve was 0.952, and the youden index was 0.829, p value was 0.001. In our study, neutrophil CD64 level showed higher diagnostic accuracy than CRP and PCT levels in the diagnosis of pediatric sepsis. In the diagnosis of sepsis, the use of neutrophil CD64 level alone or in combination with other biomarkers is seen as a valuable parameter that enables early diagnosis. However, the number of studies conducted in the pediatric age group is limited and needs to be supported by studies involving larger numbers of patients.