We found that the level of ADA in pleural or pericardial effusion was higher than 40 U/L in two cases; serum LDH was elevated in two cases (both < 460 U/L); the ratio of serum LDH to ADA in pleural or pericardial effusion was higher than 20 in one case; and the LDH level in pleural effusion exceeded 681 U/L in three cases. Here, ADA is linked to pericardial effusion.