Pleural empyema laboratory findings

Diagnosis is confirmed by thoracentesis. Aspiration of the purulent fluid is necessary especially when condition is not resolving on antibiotics. The pleural fluid typically has a low pH (<7.20), low glucose (<60 mg/dL), and contains infectious organisms. Although the presence of pus or organisms on gram stain is extremely helpful in making a diagnosis of empyema, a positive bacteria culture from pleural fluid is not needed before diagnosis of empyema is comfirmed.^[1][2]

Diagnosis is confirmed by thoracentesis. Aspiration of the purulent fluid is necessary especially when condition is not resolving on antibiotics. The pleural fluid typically has the following features:

• Low pH (<7.20)
• Low glucose (<60 mg/dL) and
• Contains infectious organisms.

Although the presence of pus or organisms on gram stain is extremely helpful in making a diagnosis of empyema, a positive bacteria culture from pleural fluid is not needed before diagnosis of empyema is comfirmed.^[1][2]

The COMPLES score has been developed to differentiate between tuberculous effusions with low pleural pH or glucose and complicated parapneumonic effusions.

The components are:

• pleural fluid adenosine deaminase (ADA) (<46 IU/L [0 points]
• The percentage of mononuclear cells (MNC %), ≥100 IU/L [6 points]), 46-100 IU/L [4 points], MNC % (<10 % [0 points], 10-50 [3 points], >50 [8 points])
• PH, pH (<7.07 [0 points], 7.07-7.20 [3 points], >7.20 [5 points]),
• Age.age (≥30 [0 points], <30 years [3 points])

A score of 12 or more points is highly sensitivity and specificity for complicated tuberculous pleural effusion.^[3]