A positive likelihood ratio of 8 and a negative likelihood ratio of 0.222 means that the likelihood of a TGF-β1 ≥ 515 ng/ml level is 8 times in patients with endometriosis and a possible TGF-β1 level <515 ng/ml is 0.222 times in nonendometriosis patients. The gene discussed is TGFB1; the disease is endometriosis.