title: Measurement of anti-dsDNA: a comparative study of two ELISA and the Crithidia assay.
abstract: We compared the measurement of anti-dsDNA by a commercial ELISA test (DIASTAT), an in-house ELISA and the Crithidia luciliae assay in cross-sectional sera samples of 209 systemic lupus erythematosus (SLE) patients and 64 patients with a variety of rheumatological, autoimmune and non-autoimmune diseases in Hong Kong. The Crithidia assay was found to be the least sensitive (17%) but most specific (95%) method for detection of a positive result in SLE patients. The DIASTAT assay has a higher sensitivity (68%) but lower specificity (80%) than the in-house ELISA test (32% sensitivity and 89% specificity). The positive predictive value of the three assays are comparable at 90-92% while DIASTAT had the highest negative predictive value (44%). There was good linear correlation (r = 0.7) between the two ELISAs. ELISA can serve as a useful screening test for anti-dsDNA in SLE patients and doubtful cases can then be confirmed by another method such as radio-immunoassay.
authors.affiliation: Department of Health, University of Hong Kong, Hong Kong.
authors.forename: K H
authors.initials: KH
authors.lastname: Wong
authors.forename: J W
authors.initials: JW
authors.lastname: Lawton
authors.forename: S K
authors.initials: SK
authors.lastname: Cheng
authors.forename: S S
authors.initials: SS
authors.lastname: Lee
authors.forename: C S
authors.initials: CS
authors.lastname: Lau
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000097:blood* / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D001327:Autoimmune Diseases / Q000097:blood / Q000276:immunology; D001681:Biological Assay / Q000379:methods; D003421:Crithidia / Q000737:chemistry / Q000276:immunology; D003627:Data Interpretation, Statistical; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000276:immunology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012871:Skin Diseases / Q000097:blood / Q000276:immunology
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies