American Board of Internal Medicine (ABIM) Certification Practice Exam

What total protein level in ascitic fluid is associated with a cardiac cause of ascites?

1. 1.0 g/dL

2. 2.0 g/dL

3. 2.5 g/dL

4. 3.0 g/dL

The correct answer is: 2.5 g/dL

The total protein level in ascitic fluid serves as an important measure to help differentiate the underlying causes of ascites. In cases of ascites due to cardiac causes, such as congestive heart failure, the protein concentration is typically indicative of a transudative process. In situations where ascites is correlated with a cardiac origin, the total protein level in the ascitic fluid is often lower, typically falling below 2.5 g/dL. However, when the protein concentration is around 2.5 g/dL, it signals a transition point; although this value can indicate the presence of a mixed process or may overlap with the criteria for exudative ascites, the 2.5 g/dL level specifically serves as a useful benchmark to observe the behavior of the fluid in relation to the underlying cardiac condition. Moreover, higher protein concentrations, such as those at 3.0 g/dL, are more commonly associated with exudative processes, which can occur due to infections, malignancies, or inflammatory conditions, rather than cardiac issues. Therefore, the selection of 2.5 g/dL as an indicator of a potential cardiac cause aligns well with clinical observations that categorize ascitic fluid according to its protein content. In