Comparison of two extractable nuclear antigen testing algorithms: ALBIA versus ELISA/line immunoassay.
Extractable nuclear antigen (ENA) antibody testing is often requested in patients with suspected connective tissue diseases. Most laboratories in Australia use a two step process involving a high sensitivity screening assay followed by a high specificity confirmation test. Multiplexing technology with Addressable Laser Bead Immunoassay (e.g., FIDIS) offers simultaneous detection of multiple antibody specificities, allowing a single step screening and confirmation. We compared our current diagnostic laboratory testing algorithm [Organtec ELISA screen / Euroimmun line immunoassay (LIA) confirmation] and the FIDIS Connective Profile. A total of 529 samples (443 consecutive+86 known autoantibody positivity) were run through both algorithms, and 479 samples (90.5%) were concordant. The same autoantibody profile was detected in 100 samples (18.9%) and 379 were concordant negative samples (71.6%). The 50 discordant samples (9.5%) were subdivided into 'likely FIDIS or current method correct' or 'unresolved' based on ancillary data. 'Unresolved' samples (n = 25) were subclassified into 'potentially' versus 'potentially not' clinically significant based on the change to clinical interpretation. Only nine samples (1.7%) were deemed to be 'potentially clinically significant'. Overall, we found that the FIDIS Connective Profile ENA kit is non-inferior to the current ELISA screen/LIA characterisation. Reagent and capital costs may be limiting factors in using the FIDIS, but potential benefits include a single step analysis and simultaneous detection of dsDNA antibodies.
Department of Immunopathology, ICPMR, Westmead Hospital, Westmead, NSW, Australia; Faculty of Medicine, University of Sydney, Sydney, NSW, Australia. Electronic address: cdinusha@gmail.com.
Dinusha
D
Chandratilleke
Department of Immunopathology, ICPMR, Westmead Hospital, Westmead, NSW, Australia.
Roger
R
Silvestrini
Department of Immunopathology, ICPMR, Westmead Hospital, Westmead, NSW, Australia.
Sue
S
Culican
Department of Immunopathology, ICPMR, Westmead Hospital, Westmead, NSW, Australia.
David
D
Campbell
Research and Education Network, Westmead Hospital, Westmead, NSW, Australia.
Karen
K
Byth-Wilson
Department of Immunopathology, ICPMR, Westmead Hospital, Westmead, NSW, Australia; Faculty of Medicine, University of Sydney, Sydney, NSW, Australia; Faculty of Medicine, Western Sydney University, Sydney, NSW, Australia.
Sanjay
S
Swaminathan
Department of Immunopathology, ICPMR, Westmead Hospital, Westmead, NSW, Australia; Faculty of Medicine, University of Sydney, Sydney, NSW, Australia.
Ming-Wei
MW
Lin
D000465:Algorithms; D034961:Antigens, Nuclear / Q000032:analysis* / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000032:analysis / Q000276:immunology; D003240:Connective Tissue Diseases / Q000175:diagnosis; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007118:Immunoassay / Q000379:methods*
D034961:Antigens, Nuclear; D001323:Autoantibodies; D001324:Autoantigens
ALBIA; ELISA; ENA; FIDIS; characterisation; connective tissue disease; line immunoassay; multiplex; screening