The ratio of albumin to lactoferrin in tear fluid as a diagnostic tool in primary Sjogren's syndrome

Purpose: To compare the protein composition of tear fluid obtained from patients with primary Sjogren's syndrome, patients with other connective tissue diseases and control individuals. Methods: SDS polyacrylamide gel electrophoresis followed by staining with Coomassie blue and Western blotting. Results: Comparison revealed the presence of a characteristic difference in the ratio of intensity between the albumin and lactoferrin bands. An albumin:lactoferrin ratio above 2:1 was significantly more common in patients with primary Sjogren's syndrome than in patients with other connective tissue diseases or the controls. Conclusion: An albumin:lactoferrin ratio above 2:1 may therefore prove of use when diagnosing 1 degrees SS. Used as a test, its sensitivity was 67% and its specificity 100%.