Table 13.13-1. Light’s criteria for distinguishing exudative from transudative pleural effusion

Light’s criteria

Sensitivity for exudate

Specificity for exudate

Exudative pleural effusion if meets ≥1 of:

98%

83%

 

Pleural fluid protein to serum protein ratio >0.5

86%

84%

Pleural fluid LDH to serum LDH ratio >0.6

90%

82%

Pleural fluid LDH >2/3 of ULN for serum LDH

82%

89%

Adapted from N Engl J Med. 2002;346(25):1971-7.

LDH, lactate dehydrogenase; ULN, upper limit of normal.