This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pleural effusion & Pulmonary alveolar proteinosis, Subject name: Medicine
All of the following are components of Light's criteria for pleural effusion except: 
Select and explain. 
A. Effusion protein/serum protein ratio greater than 0.5, B. Effusion lactate dehydrogenase (LDH)/serum LDH ratio greater than 0.6, C. Effusion LDH level greater than two-thirds the upper limit of the laboratory's reference range of serum LDH, D. Effusion sugar is less than 2/3rd of blood sugar
D: Effusion sugar is less than 2/3rd of blood sugar
Answer: D: Effusion sugar is less than 2/3rd of blood sugar 
Explanation: LIGHT CRITERIA Pleural fluid protein/Serum protein >0.5 Pleural fluid LDH/Serum LDH >0.6 Pleural fluid LDH more than two-thirds normal upper limit for serum Exudative pleural effusions meet at least one of the following criteria, whereas transudative pleural effusions meet none These criteria misidentify ~25% of transudates as exudates.