Evaluating systemic immune-inflammation indices as predictive markers for endometriosis diagnosis: A retrospective observational study

Endometriosis is a chronic inflammatory disease for which there is currently no accurate screening test to identify or predict the probability of the disease in individuals. This can often lead to delays in diagnosis. Several systemic immune-inflammation indices are currently used as predictive or supportive markers for several inflammation-associated diseases. In this study, we investigated whether these immune-inflammation indices, such as systemic immune inflammation index (SII), systemic inflammation response index (SIRI), neutrophil-to-lymphocyte ratio (NLR), and pan-immune inflammation value (PIV) could serve as predictive or supplementary markers for diagnosing endometriosis. A total of 434 women with confirmed endometriosis and 517 controls were included in this study. Data on peripheral blood tests, including total counts of white cells, neutrophils, monocytes, lymphocytes, and platelets, were collected, and systemic immune-inflammation indices were calculated. SII, SIRI, NLR, and PIV values were significantly higher in women diagnosed with endometriosis compared to controls. Using the cut-off values of 538 for SII, 0.814 for SIRI, 2.03 for NLR, and 210 for PIV, we achieved 76 % sensitivity and 70 % specificity. When the four indices were combined, the area under the ROC curve (AUC) was 0.796 (95 % CI: 0.766, 0.827), with 76 % sensitivity and 70 % specificity. In conclusion, while ultrasonography or MRI remains the gold standard for visualizing the lesions in diagnosing endometriosis, followed by laparoscopy and histologic verification, routine peripheral blood tests in combination with clinical symptoms, could provide additional clinical diagnostic value for endometriosis as a non-invasive and cost-effective test.