17th February 2025

A 65-year-old gentleman with a history of congestive heart failure and cough is investigated for a pleural effusion.

A 65-year-old gentleman with a history of congestive heart failure and cough is investigated for a pleural effusion. 

Investigations are as follows:

CRP 160 (<5)

On pleural aspiration, the fluid is clear, with a pH of 7.1 and a glucose level of 2.5. 

Which of these features is diagnostic for a complicated parapneumonic effusion?

Select the SINGLE most appropriate option from the list below. Select ONE option only.