The pleural fluid LDH/ADA ratio of tuberculous pleurisy (median 5.1 [IQR 3.4–8.0]) was lower than those of pleural infection (median 51.5 [IQR 33.2–78.0], p < 0.001), malignant pleural effusion (median 20.6 [IQR 8.0–37.8], p < 0.001), ML (median 18.4 [IQR 7.3–24.1], p = 0.011), and other diseases (median 28.5 [IQR 16.7–49.1], p < 0.001). Here, ADA is linked to pleural tuberculosis.