A 60-year-old man presents with dyspnea. Pleural fluid analysis shows a protein concentration of 3.8 g/dL, LDH of 280 U/L, and a specific gravity of 1.025. Based on these findings, this effusion is classified as:

• A Transudate, because the protein exceeds 3 g/dL
• B Transudate, because the LDH is below 300 U/L
• C Exudate, reflecting increased vascular permeability ✓
• D Pseudochylous effusion, indicating lymphatic obstruction

Explanation

An exudate is an inflammatory fluid rich in proteins (>3 g/dL), cellular debris, and often inflammatory cells, with a specific gravity above 1.020. The elevated protein and specific gravity here indicate increased vascular permeability typical of exudates. Option B is the trap: transudates are defined by low protein and specific gravity below 1.012 to 1.020, and LDH cutoffs alone do not reclassify a clearly protein-rich fluid as a transudate.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.