dsDNA antibodies (Crithidia)

dsDNA Crithidia luciliae is an indirect immunofluorescent assay for the screening and semi-quantitative determination of anti-double stranded DNA (dsDNA) in human serum. The presence of anti-double stranded DNA can be used in conjunction with other serological tests and clinical findings to aid in the diagnosis of systemic lupus erythematosus (SLE). In general, anti-native dsDNA antibodies are not found in other rheumatic diseases, but if present, their titre is usually lower than those in SLE patients. They may be seen in autoimmune chronic active hepatitis and in rheumatoid arthritis treated with sulphasalazine.