Because different culture media give different results with the lysozyme test for the diagnosis of the sicca syndrome, the procedure has been standardized for a commercially available medium. Diagnostic sensitivity test agar (Oxoid, Flow Laboratories, Inc, Rockville, Md) was chosen as medium for its superior discrimination and convenience in preparation. The new diameter lysis limit between normality and disease on diagnostic sensitivity test agar is 22.5 mm. Heart infusion broth (Difco) is used as broth culture to flood the medium with Micrococcus lysodeikticus. The M lysodeikticus strain we used throughout the studies has been deposited at the American Type Culture Collection under accession No. 27523.