Study objectives: To determine the bronchoscopist's ability to predict specimen quality at the time of transbronchial biopsy and to determine the influence of biopsy specimen size and alveolar content on diagnostic value.
Design: Prospective, blinded, observational analysis.
Setting: Tertiary care academic hospital-based pulmonary practice.
Patients: Forty-three adult patients who underwent transbronchial lung biopsy.
Interventions: Each of 170 biopsy specimens was rated as to likelihood of containing diagnostic tissue, size and ability to float, tissue types present, number of alveoli, and pathologic diagnosis.
Results: Fifteen percent of biopsy specimens were small and 40% were large. Seventy-six percent of specimens floated; 61.8% of the 170 biopsy specimens contained abnormal lung tissue; and 14.7% of individual specimens were diagnostic. Fifty-two percent of specimens contained >20 alveoli. Larger biopsy specimens were more likely to contain diagnostic tissue (r=0.29, p=0.001). Cup forceps retrieved smaller pieces of tissue (p=0.007) and were less likely to obtain diagnostic tissue (p=0.06). Physician ratings of specimen quality (mean±SD) did not differ between specimens containing normal and abnormal tissue (5.98±2.3 vs 5.46±5.5; p=0.24) or between specimens containing diagnostic vs nondiagnostic tissue (5.56±2.5 vs 6.25±2.1; p=0.14). Specimens that floated were no more likely to be diagnostic or abnormal than specimens that sank (p<0.05). Diagnosis when established was made by the first biopsy specimen in 53.3% and the second in 33.3%
Conclusions: Physician estimate of biopsy specimen quality and the float sign are not helpful in predicting that the biopsy specimen contains abnormal or diagnostic tissue. Diagnostic biopsy specimen will likely be obtained if the size of the specimen fills the forceps, 2 to 4 biopsies are performed, and toothed forceps are used.