1. P_Protein/S_Protein > 0.5
2. P_LDH/S_LDH = 257/120 > 0.6
3. P_LDH > 2/3 of ULN of S_LDH (value given by each lab)
   • a.k.a. P_LDH = 130-150 IU

Where P = pleural, S = serum

If meet any of the criteria: Exudate

Light's Criteria for Exudative Effusions