Perry Carditis is a 73 year old gentleman who has been admitted with rigors and shortness of breath. On assessment, his oxygen saturations are 82% on room air. He has a 40 pack year history of smoking and has noticed 5 kilograms of weight loss over the past 4 months. A chest x-ray shows a new pleural effusion. Your registrar performs a pleuritic tap with the results shown below.
