Observer variation in the detection of osteopenia.

In order to determine observer variation in the detection of osteopenia, 15 pairs of lateral chest radiographs obtained within two weeks of each other were reviewed separately by two radiologists and one orthopedist on three separate occasions. Intra- and interobserver variations were calculated for each individual film and film pairs using Kappa values. The individual observers were not able to give consistent readings on the same film on different days (average Kappa = 0.54). When the additional factors of repeat films (average kappa = 0.47), or separate observers (average Kappa = 0.38) were analyzed, agreement was even worse. The identification of osteopenia from the lateral view of the thoracic spine is highly subjective and variable from film to film and observer to observer.