TableĀ 4
Classification of exudate by each Light's criterion
Laboratory
Pleural fluid to serum protein >0.5
Pleural fluid to serum LDH >0.6
Pleural fluid LDH is >2/3 the upper reference limit for serum LDH
A
21
18
26
B
24
14
15
C
25
12
9
LDH, lactate dehydrogenase.