Percutaneous needle biopsy of musculoskeletal lesions. 1. Effective accuracy and diagnostic utility.

The utility of a diagnostic test depends not only on its accuracy but also on how its results affect clinical management. We reviewed the results of 102 percutaneous needle biopsies to determine the accuracy, effective accuracy, and diagnostic utility of the procedure. We found percutaneous needle biopsy was similarly accurate in identifying suspected metastatic lesions (82%, n = 44), suspected musculoskeletal infections (90%, n = 29), and suspected primary musculoskeletal tumors (83%, n = 29). Effective accuracy, or accuracy discounted for results with limited clinical utility, was highest in identifying suspected metastatic deposits (77%), slightly lower in suspected infections (72%), and lowest in suspected primary tumors (59%). Diagnostic utility (the probability-weighted sum of the utility values of all possible outcomes of a diagnostic test) for identifying metastatic deposits and infections exceeded that for suspected primary tumors. Percutaneous needle biopsy in patients with suspected primary tumors must be performed with the knowledge that, even though technically accurate, such biopsies may be of limited clinical value. Percutaneous needle biopsy of suspected metastatic lesions and suspected infections, on the other hand, offers high accuracy and high diagnostic utility.