Light's Criteria Calculator Differentiate Exudative vs. Transudative Pleural Effusions. Pleural Fluid Protein (g/dL) Serum Protein (g/dL) Pleural Fluid LDH (U/L) Serum LDH (U/L) Serum LDH Upper Limit of Normal (U/L) Calculate The pleural effusion is likely Criteria Met: