. Author manuscript; available in PMC: 2022 Oct 1.

Published in final edited form as: Respir Med. 2021 Jul 28;187:106553. doi: 10.1016/j.rmed.2021.106553

Table 1.

Parapneumonic Effusion Definitions

Type	Category	Definition	Glucose	pH	Cultures
Uncomplicated	1	Effusion is < 10-mm thickness	Normal	Normal	Negative
Uncomplicated	2	Effusion is > 10-mm thickness and occupies < 50% of hemithorax	Normal	Normal	Negative
Complicated	3	Effusion occupies ≥ 50% of hemithorax, is loculated, or with thickened pleura	↓	↓	Positive
Empyema	4	Effusion occupies ≥ 50% of hemithorax, is loculated, or with thickened pleura, but frank pus is present	↓	↓	Positive