Iranian Journal of Nursing and Midwifery Research1735-906617220120307671671ENMSc, Nursing and Midwifery Care Research Center, Department of Midwifery, School of Nursing and Midwifery, Isfahan University of Medical Sciences, Isfahan, Iran.PhD, Water and Electrolytes Research Center, Kidney Diseases Research Center, Department of Physiology, Isfahan University of Medical Sciences, Isfahan, Iran.MD, Gynecologist, Isfahan Fertility and Infertility Center, Isfahan, Iran20120307<ul><li><strong>Background:</strong> Endometriosis is defined as the existence of endometrial-like tissue outside the uterus. Diagnosis of endometriosis is a challenging theme. Despite the broad search for innovative laboratory tests and advances in imaging technologies, there are still no easy, non-invasive diagnostic tests available. Due to inflammatory process of endometriosis, still C-reactive protein (CRP) level may be the target of initial screening. The aim of this study was to investigate CRP levels as a marker of inflammatory process in serum and peritoneal fluid of patients with endometriosis.</li><li><strong>Materials and Methods:</strong> In a case control study, 179 patients with endometriosis (N = 90) and without endometriosis <br /> (N = 89) were evaluated. The venous blood samples were obtained from all patients before laparoscopy and the peritoneal fluid samples were collected from pelvis before any manipulation. Student&rsquo;s t-test was applied to compare the parameters between two groups.</li><li><strong>Findings:</strong> There was no significant difference between the CRP serum level in patients with endometriosis and infertile women without endometriosis. There was a significant difference in peritoneal level of CRP between case and control groups (p &lt; 0.05).</li><li><strong>Conclusions:</strong> The findings suggested that measurement of this marker in patients&rsquo; serum or plasma cannot be used to diagnose endometriosis. It is further recommended that a combination of different markers might be helpful in this regard that could be studied in future.</li><li>&nbsp;<strong>Key words</strong><strong>:</strong>&nbsp;Endometriosis, inflammation, C-reactive protein, serum, peritoneal fluid, infertility</li></ul>http://ijnmr.mui.ac.ir/index.php/ijnmr/article/view/671http://ijnmr.mui.ac.ir/index.php/ijnmr/article/download/671/478