Confirmatory tests for the dry eye of Sjögren's syndrome.

The diagnosis of moderate degrees of tear depletion is difficult using conventional tests such as the Schirmer test, clinical evidence and even a confirmatory test such as the lysozyme test. We have refined the lysozyme test using quantitative techniques and calibrated standards. We found this satisfactory on a population basis, but not on an individual basis. We developed an ELISA test for assaying five tear proteins 'lysozyme, lactoferrin, ceruloplasmin, IgA and IgG' which gives a much more accurate assessment of dryness on an individual patient level.