Light’s criteria for distinguishing exudative from transudative pleural effusion

Table 17.16-1. 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.