A Prospective Study of the Volume of Pleural Fluid Required for Accurate Diagnosis of Malignant Pleural Effusion.
Chest. 2008 Nov 18;
Authors: Abouzgheib W, Bartter T, Dagher H, Pratter M, Klump W
This is a prospective study to define the volume of pleural fluid adequate for maximal yield of cytologic analysis of pleural fluid. Patients undergoing diagnostic thoracentesis with malignancy in the differential diagnosis were enrolled. The first 50cc of pleural fluid were put in a specimen cup and subsequent fluid was collected in a drainage bag. Both samples were sent for cytologic evaluation. The cytologist was blinded as to which specimen was being evaluated. Forty-four patients (21 m, 23 f, age 46 +/- 11.1 year) were enrolled. Average volume of the "large volume" specimen was 890 +/- 375 mL (range 250-1800). Although malignant pleural involvement had never been documented for any, 31 patients had had a diagnosis of malignancy prior to thoracentesis. Cytology was positive for malignancy in 23 out of the 44 cases (55%). In the group of patients with an established history of cancer, the pleural fluid was positive for malignant cells in 19 of 33 samples (58%). In all 23 patients with malignant pleural effusion, both the 50cc specimen and the large volume specimen were cytologically identical. In all 21 patients with negative pleural cytology, there was again 100% concordance between 50cc samples and the larger samples. The minimum adequate pleural fluid volume for cytologic diagnosis has been a matter of debate. The strongest data to date came from a retrospective study in 2002. Our prospective study now unequivocally supports the concept that the submission of > 50cc of pleural fluid for cytologic analysis does not increase diagnostic yield.
PMID: 19017891 [PubMed - as supplied by publisher]