fa پژوهشي اصیل Original Research <strong>Background and Objectives</strong>: Urinary Tract Infections (UTI) is a common disorder in pediatrics and early diagnosis is important. However, in young children diagnosis is problematic. A problem is variety in sign and symptoms and for exact diagnosis in some case we need expensive modalities. Thus, new way is needed. IL-6 at last decades was preferred to UTI diagnosis and upper/lower involvement differentiation. According to contrariety in IL-6 accuracy this study was performed to learn about diagnostic accuracy of plasma IL-6 in UTI diagnosis and its power for differentiating upper from lower involvement.<br> <strong>Methods:</strong> At this descriptive study, 83 patients were included and examined for Interleukin 6 value in both urinary tract diagnosis and upper/lower involvement differentiation. Demographic characteristic like age, gender, history, physical examination beside of blood tests like white blood cell count, ESR, CRP, IL-6 were done and results listed. Descriptive parameters were reported by mean and frequency and for statistical analysis was performed using t-test in SPSS v.16. ROC curve was checked for diagnosed value.<br> <strong>Results:</strong> In this study 83 patients (14 control group, 33(39.8%) cystitis, 36(43.4%) pyelonephritis) with 3.93&plusmn;3.069 mean age enrolled. Age distribution at this study was 20, 63 for males and females, respectively. The IL-6 level in cystitis was higher than control and but was not significant. In ROC curve sensitivity and specify of IL-6 for cystitis were 52%, 50% and for pyelonephritis 60%, 50%, respectively.<br> <strong>Conclusion:</strong> According to this study, IL-6 is not a good biomarker for Urinary tract infection and differentiation upper tract involvement from the lower tract. A wide range of Il-6 level and useless of this biomarker can be due to gender distribution, time of disease presence, bacterial virulence and other factors. Therefore, studies on large sample is recommended.<br> &nbsp; 13 18 http://ijca.iums.ac.ir/browse.php?a_code=A-10-1-60&slc_lang=fa&sid=1 Rama Naghshidaian 1003194753284600646 1003194753284600646 Yes urdistan University of Medical Sciences, Sanandaj, Iran Rasoul Nasiri Kalmarzi 1003194753284600647 1003194753284600647 No University of Medical Sciences, Sanandaj, Iran Alireza Eskandarifar 1003194753284600648 1003194753284600648 No Kurdistan University of Medical Sciences, Sanandaj, Iran Behzad Khalafi 1003194753284600649 1003194753284600649 No Kurdistan University of Medical Sciences, Sanandaj,Iran Ahmad Fotoohi 1003194753284600650 1003194753284600650 No Kurdistan University of Medical Sciences, Sanandaj,Iran Soroush Noshadi 1003194753284600651 1003194753284600651 No Iran University of Medical Sciences, Tehran, Iran Hedayat Rasouli 1003194753284600652 1003194753284600652 No Kurdistan University of Medical Sciences, Sanandaj,Iran