Actually, the question should be: "What tests are done on pleural fluid to evaluate pleural effusion?" Because the tests are not done on blood, but on the pleural fluid itself. The routine evaluation of pleural fluid includes several tests, not just one. These tests help determine the cause of the pleural effusion.
Pleural Fluid Analysis
The analysis of pleural fluid typically includes the following:
- Protein Level: Helps differentiate between transudative and exudative effusions.
- pH: Low pH can indicate infection, malignancy, or esophageal rupture.
- Lactate Dehydrogenase (LDH): Elevated levels suggest inflammation or cell damage.
- Glucose: Low glucose levels may be seen in empyema or rheumatoid pleurisy.
- Albumin: Used in conjunction with serum albumin to calculate the serum-pleural fluid albumin gradient, aiding in the differentiation of transudates and exudates.
- Adenosine Deaminase (ADA): Elevated levels can suggest tuberculosis.
- Cell Count and Differential: Determines the number and types of cells present, which can indicate infection, inflammation, or malignancy.
- Cytological Examination: Microscopic examination of the fluid to detect malignant cells.
