To diagnose MM, the accuracy of pleural HA >30,000 ng/mL revealed a sensitivity of 75.0%, specificity of 72.6%, and odds ratio of 7.94 (95% CI: 2.5–25.2, P = .001); pleural CEA <6.0 ng/mL revealed a sensitivity of 95.2%, specificity of 84.9%, smaller negative likelihood ratio of 0.06, and odds ratio of 112.5% (95% CI: 14.4–878.1, P < .001). Here, CEACAM5 is linked to Miyoshi myopathy.