Would you perform a diagnostic paracentesis for first-time ascites in a patient with established CHF or pulmonary hypertension, but without apparent liver or other intra-abdominal disease?

Great question. Yes, we should perform a diagnostic paracentesis for first-time ascites, even in patients with established CHF or pulmonary hypertension, unless there is an obvious alternative explanation and the procedure is unsafe or technically not feasible. After the etiology is established, repeat paracenteses are rarely needed unless clinical features change (the patient is symptomatic or an alternative etiology is suspected).

First-time ascites = unknown ascites.

Guidelines and expert con...

Typically, yes, I'd recommend and pursue a low‑volume diagnostic tap (for cell count/diff, albumin, total protein ± culture) even if the working diagnosis is cardiac ascites driven by CHF or pulmonary hypertension - exceptions based on goals of care, too small to safely tap, patient preference after understanding risks/benefits.

I agree with the answer below, imaging of the liver, especially on CT, does not always accurately tell cirrhosis.