Method Description

Patient serum with a positive screen at the 1:10 dilution is titered up to 1:640 and allowed to bind to the kinetoplast of the non-pathogenic hemoflagellate Crithidia luciliae adhered to the slide. The Crithidia luciliae contains a dense, pure concentration of circular double-stranded DNA that provides a unique substrate free from contaminating nuclear antigens like histones or single-stranded DNA. Following binding, unbound diluted patient serum is washed off the slide and fluorescent-conjugated antiserum added to the substrate on the slide and incubated. A second washing step is performed to remove excess conjugate. The substrate is cover slipped and reviewed for fluorescent patterns with a fluorescent microscope. Observation of specific fluorescent patterns on the substrate indicate the presence of autoantibodies in the test sample. Positive results are reported with an end point titer up to 1:640. Results higher than 1:640 are reported as greater than 1:640.(Package Insert: Immuno Concepts IgG ANTI-nDNA Fluorescent Test System, Immuno Concepts, Rev 4.0 2023)