This study aimed to evaluate the concentration of osteopontin in peritoneal fluid and plasma as potential biomarkers for diagnosing endometriosis. Osteopontin levels were measured using surface plasmon resonance imaging (SPRI) biosensors in patients suspected of having endometriosis. Plasma samples were collected from 120 patients, and peritoneal fluid was collected from 86 patients. Based on the detection of endometriosis lesions during laparoscopy, participants were divided into a study group (patients with endometriosis) and a control group (patients without endometriosis). The results showed no significant differences in plasma osteopontin levels between women with endometriosis and the control group (19.86 ± 6.72 ng/mL vs. 18.39 ± 4.46 ng/mL, p = 0.15). Similarly, peritoneal fluid osteopontin concentrations did not differ significantly between patients with and without endometriosis (19.04 ± 5.37 ng/mL vs. 17.87 ± 5.13 ng/mL, p = 0.29). Furthermore, osteopontin levels in both plasma and peritoneal fluid were not significantly associated with the stage of endometriosis, the presence of endometrioma, or the menstrual cycle phase. The findings of this study do not support osteopontin concentration as a reliable biomarker for endometriosis. However, further research is necessary to explore osteopontin’s potential role in the disease.

Background: The relationship between low-grade inflammation and anti-Müllerian hormone (AMH) in Polyendocrine Metabolic Ovarian Syndrome (PMOS) remains incompletely understood. This study aimed to compare inflammatory markers and AMH concentrations between non-obese women with PMOS and controls and to assess the associations between these markers and AMH. Methods: This single-centered retrospective study involved 92 patients divided into two groups: a control group of 45 patients and 47 patients newly diagnosed with PMOS according to Rotterdam criteria. Results: Compared with controls, patients with PMOS had significantly higher median concentrations of CRP (3.902 vs. 1.038), IL-6 (4.15 vs. 2.28), and TNF-α (3.35 vs. 1.95), as well as higher white blood cell and lymphocyte counts. Median AMH (6.47 vs. 3.04), LH (8.77 vs. 6.93), and testosterone (0.415 vs. 0.317) concentrations were also significantly higher in the PMOS group. Conversely, NLR and PLR were higher in controls. When both groups were analyzed together, AMH correlated positively with IL-6 (r = 0.53), CRP (r = 0.53), TNF-α (r = 0.54), LH (r = 0.50), and testosterone (r = 0.44). In the pooled cohort, AMH correlated positively with CRP, IL-6, and TNF-α. Although TNF-α was significantly associated with AMH in the initial multivariable quantile regression models, these associations were no longer statistically significant after adjustment for PCOS/control status. Group status remained significantly associated with AMH at the 90th percentile. Conclusions: No statistically significant correlations were found between AMH levels and inflammatory markers in non-obese patients with PMOS or in healthy women.