Study objectives: To determine the optimal number of pleural biopsy (PLBX) specimens for a diagnosis of tuberculous pleurisy.
Design: Retrospective review.
Setting: County hospital.
Methods: We reviewed all percutaneous needle biopsy specimens of the parietal pleura in 30 patients who had tuberculous pleurisy. Data are reported as mean+/-SEM and statistical comparisons are done with the Mann-Whitney test. We accepted p<0.05 as statistically significant.
Results: The number of biopsy specimens obtained from each patient ranged from 4 to 10 with 1 sample submitted for mycobacterial culture and the rest submitted for histologic study. Sixty percent of patients had pleural cultures positive for Mycobacterium tuberculosis and 80% had diagnostic histology. Overall pleural biopsy sensitivity (histology and culture) for tuberculous pleurisy was 87%. On average, 40.4%+/-4.7% of all PLBX specimens contained pleura. Diagnostic PLBX procedures compared to false-negative procedures produced more tissue specimens (7.1+/-0.3 vs 4.8+/-0.5, p=0.005) containing more pleural specimens (2.4+/-0.2 vs 0.8+/-0.5, p=0.01). If only PLBX procedures yielding more than six tissue specimens (n=18) or more than two pleural specimens (n=12) were analyzed, then the diagnostic sensitivity of PLBX for pleural tuberculosis was 100%. There seemed to be a direct relationship between the sensitivity of PLBX and the number of specimens submitted.
Conclusions: The sensitivity of percutaneous needle biopsy for diagnosis of tuberculous pleurisy is highest when more than six specimens are obtained which, on average, contain more than two specimens of parietal pleura. There are no conclusive data indicating how many tissue specimens to submit for mycobacterial culture, but one specimen seems sufficient.