Transbronchial Lung Biopsy in Sarcoidosis

In order to determine if the diagnostic yield of the transbronchial lung biopsy in sarcoidosis is dependent upon the number of biopsies, a study was designed to examine individual specimens from 6 biopsies in patients with Stage II sarcoidosis. It was found that the probability of obtaining a positive specimen per biopsy was 46%, and this percentage remained constant for each biopsy. The diagnostic yield followed a logarithmic curve, gradually increasing from 1 through 4 biopsies until about 90% of true positive diagnoses were obtained, then approaching a plateau with successive biopsies. We therefore recommend that 4 transbronchial lung biopsies are sufficient to diagnose stage II sarcoidosis in the majority of patients with diffuse lung disease.