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To assess the utility of various laboratory tests used to diagnose autoimmune inner ear
Retrospective study of 82 patients evaluated at the University of Washington Otology Clinic from 1996 through 1998 with review of clinical history, laboratory tests, audiograms, response to therapy, and final diagnoses.
Charts were reviewed for presenting history and initial workup including test results for erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Clq binding assay, anticardiolipin antibody (aCL), antineutrophil cytoplasmic antibody (ANCA), microhemagglutinin assay for Treponema pallidum (microhemagglutination assay),
Lyme disease titers, and the Western blot for heat shock protein 70 (hsp 70).
The Western blot for hsp 70 is the best test for predicting corticosteroid responsiveness. The sensitivity was low at 42%, although the specificity was 90%, and the positive predictive value of this test was excellent at 91%. The ESR was as good as the CRP in detecting acute-phase reactants. The other, more specific tests in the laboratory panel (aCL, ANCA, MHA, and
Lyme disease titers) did not detect any new cases of autoimmune
disease in addition to those which were already identified by an abnormal ESR.
A diagnostic test panel for autoimmune inner ear
disease should include an ESR and the Western blot for hsp70. More specific laboratory testing for systemic
disease is warranted when the ESR is elevated. In patients with a positive Western blot, a trial of corticosteroid therapy can be given with good conviction because the test is quite specific. However, many people who are Western blot negative may also respond to corticosteroid therapy because the test lacks sensitivity.