fluid with a low protein level and low specific gravity

Pleural effusions are classified as either exudative or transudative.

A pleural effusion qualifies as an exudate with the one or more of the following criteria:

• pleural to serum LDH ratio of >0.6,
• pleural: serum protein ratio >0.5,
• total protein >3 g/dL, or
• pleural fluid LDH >2/3 the normal upper limit of serum LDH (200 - 300).
  • normal serum LDH? 140 units per liter (U/L) - 280 U/L

Transudative effusions usually are due to a change in hydrostatic or oncotic pressure, as in conditions such as:

• congestive heart failure
• liver cirrhosis, and
• nephrotic syndrome.

The patient in the above scenario has pleural effusions secondary to congestive heart failure, which makes transudative fluid the correct statement.