CXCL8 and endometriosis: The endometriosis cases who reported using analgesics prior to the blood draw and had acyclic pelvic pain had lower levels of IL-8 compared to those without acyclic pelvic pain (p = 0.05), while no association between acyclic pelvic pain and IL-8 was observed for the endometriosis cases who were not taking analgesics prior to the blood draw.