A 58-year-old man with known alcoholic liver cirrhosis presents to the Emergency Department with increasing abdominal distension, confusion, and a fever of 38.2°C over the past 48 hours. On examination, he has shifting dullness, a fluid thrill, and asterixis. An urgent abdominal paracentesis is performed. Which of the following ascitic fluid findings would be most diagnostic of Spontaneous Bacterial Peritonitis (SBP)?