Neutrophil-to-lymphocyte ratio as an adjunct to CA-125 for the diagnosis of endometriosis

OBJECTIVE: To investigate the clinical value of differential white blood cell counts and neutrophil-to-lymphocyte ratio (NLR), by themselves or as adjunct to CA-125, in the diagnosis of endometriosis. DESIGN: Retrospective study. SETTING: University Medical Center. PATIENT(S): Two hundred thirty-one patients with endometriosis, 145 patients with benign ovarian tumors, and 384 healthy controls participated in this study. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Sensitivities and specificities of differential white blood cell (WBC) counts, NLR, serum CA-125, and the combined marker (NLR and serum CA-125) were evaluated by receiver-operating characteristic (ROC) analysis. RESULT(S): The mean NLR and the combined marker in patients with endometriosis were significantly higher than those in patients without endometriosis. The NLR was able to discriminate patients with endometriosis from those with benign ovarian tumors and from healthy controls, and 25 of the 38 endometriosis patients (65.8%) with minimal-to-mild disease exceeded the cutoff value. The combined marker had a sensitivity of 69.3% and specificity of 83.9% with a cutoff value of 55.7, showing 13.5% increase in sensitivity but 8.9% decrease in specificity when compared with serum CA-125 at a cutoff level of 35 IU/mL. The elevated combined marker detected 16 patients with endometriosis (42.1%) with minimal-to-mild disease, whereas only 10 patients (26.3%) had their serum CA-125 levels at more than 35 IU/mL. CONCLUSION(S): Measurement of NLR and the combined marker may be used as simple and easily obtained diagnostic markers for endometriosis.