Pleural fluid is classified into two main categories: #exudate and #transudate, based on its composition and the underlying cause.

Exudate Pleural Fluid:

*High protein content (>3g/dL)
*High lactate dehydrogenase (LDH) levels (>200 IU/L)
*Low pH (<7.2) *High white blood cell count (>1000 cells/μL)
*Presence of bacteria, cancer cells, or other pathogens
*Usually caused by:

• Infections (pneumonia, tuberculosis)
• Cancer (lung, breast, lymphoma)
• Inflammatory diseases (rheumatoid arthritis, lupus)
• Trauma or surgery

Transudate Pleural Fluid:

*Low protein content (<3g/dL) *Low LDH levels (<200 IU/L) *Normal pH (>7.2)
*Low white blood cell count (<1000 cells/μL)
*No pathogens or cancer cells present
*Usually caused by:

• Heart failure
• Liver cirrhosis
• Kidney disease
• Malnutrition

Key differences:

*Protein content: Exudate has high protein, while transudate has low protein.
*LDH levels: Exudate has high LDH, while transudate has low LDH.
*pH: Exudate has low pH, while transudate has normal pH.
*Cell count: Exudate has high cell count, while transudate has low cell count.
*Underlying cause: Exudate is often caused by infections, cancer, or inflammation, while transudate is often caused by heart, liver, or kidney disease.

Accurate classification of pleural fluid is crucial for proper diagnosis and treatment.