Evaluation of laboratory examinations in asbestos-exposed patients with special reference to the relation between KL-6 and asbestos-related lung disease

The purpose of this study was to investigate the usefulness of various tests for the diagnosis of asbestos-related lung diseases, we analyzed laboratory findings of persons who underwent medical checkup for asbestos-exposure. We reviewed the medical records of persons who underwent the medical checkup for asbestos exposure at the Department of Respiratory Medicine, Chugoku Rosai General Hospital between September 2005 and December 2006. We reviewed data from blood and biochemical tests, chest X-ray, chest CT, and pulmonary function test of each subject. Subjects younger than 35 years without occupational asbestos-exposure were excluded. Among 106 subjects, 60 cases were diagnosed as having asbestos-related lung disease. Fifty-four had pleural plaque, 4 had diffuse pleural thickening, 5 had benign asbestos pleural effusion, 4 had rounded atelectasis, and 19 had asbestosis. Based on the results of chest CT scan, subjects were categorized into three groups: 46 subjects without abnormal findings due to asbestos, 41 subjects with pleural lesion, and 19 with pulmonary lesion. Laboratory examinations were compared between three groups. KL-6, carcinoembryonic antigen (CEA) and % diffusing capacity for carbon monoxide (%DLCO) were significantly different between the three groups (p<0.001 p=0.01 and p=0.03). CEA and %DLCO were significantly different between smokers and non-smokers but KL-6 did not show any significant difference. Receiver operator curve analysis showed that KL-6 had a higher diagnostic value for asbestos-related lung diseases and asbestosis than CEA and %DLCO. KL-6, which is not influenced by smoking, was thought to closely reflect fibrotic changes due to asbestos-exposure. (author)