American Board of Internal Medicine (ABIM) Certification Practice Exam

In patients with cirrhosis, what is a concerning level of ascitic fluid protein for SBP?

1. Less than 1 g/dL

2. Between 1 and 1.5 g/dL

3. Greater than 1.5 g/dL

4. None of the above

The correct answer is: Less than 1 g/dL

In patients with cirrhosis, a concerning level of ascitic fluid protein for the development of spontaneous bacterial peritonitis (SBP) is a protein level of less than 1 g/dL. This is because lower protein levels in ascitic fluid can indicate a decreased ability of the fluid to fight infections. Patients with ascites and lower protein concentrations are at greater risk for SBP because lower protein levels correlate with a lower concentration of immunoglobulins and other proteins that contribute to fluid's protective mechanisms against infection. Specifically, an ascitic fluid protein level of less than 1 g/dL indicates that the patient is likely to be at higher risk for developing SBP and requires careful monitoring and possible prophylactic treatment. Higher levels of ascitic fluid protein, particularly those above 1 g/dL, typically reflect a relatively better immune response capability, thus posing a lower risk for SBP in these patients. They suggest that there are more proteins available in the ascitic fluid, which can help fight off infections. Therefore, a level of less than 1 g/dL is a significant marker of concern in this context.