What is Glucose Protein- Pleural fluid?

Pleural fluid analysis is a test that examines a sample of fluid that has been collected in the pleural space. This is the space between the lining of the outside of the lungs (pleura) and the wall of the chest. When fluid collects in the pleural space, the condition is called pleural effusion.

Thoracentesis should be performed for new and unexplained pleural effusions when sufficient fluid is present to allow a safe procedure. Observation of pleural effusion is reasonable when benign etiologies are likely, as in the setting of overt congestive heart failure, viral pleurisy, or recent thoracic or abdominal surgery.

Laboratory testing helps to distinguish pleural fluid transudates from exudates. However, certain types of exudative pleural effusions might be suspected simply by observing the gross characteristics of the fluid obtained during thoracentesis. Note the following:

• Frankly purulent fluid indicates an empyema
• A putrid odor suggests an anaerobic empyema
• A milky, opalescent fluid suggests a chylothorax, resulting in most often from lymphatic obstruction by malignancy or thoracic duct injury by trauma or surgical procedure
• Grossly bloody fluid may result from trauma, malignancy, postpericardiotomy syndrome, or asbestos-related effusion and indicates the need for a spun hematocrit test of the sample. A pleural fluid hematocrit level of more than 50% of the peripheral hematocrit level defines a hemothorax, which often requires tube thoracostomy
• Black pleural fluid suggests a limited number of diseases, including infection with Aspergillus niger or Rhizopus oryzae, malignant melanoma, non-small cell lung cancer or ruptured pancreatic pseudocyst, or charcoal-containing empyema

Normal pleural fluid

Normal pleural fluid has the following characteristics:

• Clear ultrafiltrate of plasma that originates from the parietal pleura
• A pH of 7.60-7.64
• Protein content of less than 2% (1-2 g/dL)
• Fewer than 1000 white blood cells (WBCs) per cubic millimeter
• Glucose content similar to that of plasma
• Lactate dehydrogenase (LDH) less than 50% of plasma