A Minimum Volume of More Than 60 mL Is Necessary for Adequate Cytologic Diagnosis of Malignant Pericardial Effusions

Are we removing enough pericardial fluid to allow a diagnosis of malignant effusion?  The authors reviewed  480 pericardiocentesis specimens by comparing the percentage of malignant diagnoses ("malignancy fraction") by the volume submitted for analysis.  Using pericardial biopsy as the standard,  the sensitivity for the diagnosis of malignancy was 18.1% vs. 10.6% if more or less than 60 mL was submitted, respectively.  These results beg the following questions:  1.  Did patients with pericardial malignancies tend to have larger effusions and therefore larger aspirations?  2.  Was more fluid aspirated or submitted in patients with a higher index of suspicion for malignancy?