Performance evaluation of a novel chemiluminescence assay for detection of anti-GBM antibodies: an international multicenter study.

Abstract

BACKGROUND:

Autoantibodies to the non-collagen region (NC1) of the alpha-3 subunit of collagen IV represent a serological hallmark in the diagnosis of Goodpasture's syndrome (GPS). The objective of our study was to carefully analyze the performance characteristics of a novel anti-glomerular basement membrane (GBM) chemiluminescence immunoassay (CIA).

METHODS:

Sera from patients with GPS (n = 90) were collected from four clinical centers. Samples from different disease groups (n = 397) and healthy individuals (n = 400) were used as controls. All samples were tested for anti-GBM antibodies by a rapid, random access CIA (QUANTA Flash™ GBM). Most of the samples were also tested using other methods including different commercial anti-GBM IgG assays and research assays for anti-GBM IgA and IgM.

RESULTS:

The sensitivity and specificity of the novel CIA was 95.6% [95% confidence interval (CI) 89.0-98.8%] and 99.6% (95% CI 98.9-99.9%), respectively. Receiver operating characteristic analysis showed good discrimination between GPS patients and controls. The area under the curve was 0.98 (CI 0.96-1.0). The three anti-GBM antibody-positive samples from the control group were from two healthy individuals and one human immunodeficiency virus (HIV)-infected patient. All three individuals had low levels of anti-GBM antibodies [20, 24 and 25 chemiluminescent unit (CU), cutoff 20 CU]. When the results of the new CIA were compared to other methods, good agreement was observed: 95.8% (kappa = 0.92) versus EliA™ GBM, 97.4% (kappa = 0.95) versus both BINDAZYME™ Anti-GBM and QUANTA Lite® GBM. Anti-GBM IgA was detectable in low concentrations in patients with GPS and was associated with anti-GBM IgG but was less useful in discriminating GPS patients and controls. No discrimination was found for anti-GBM IgM.

CONCLUSION:

The novel QUANTA Flash™ GBM CIA demonstrated good sensitivity and specificity and had good agreement with other methods. Our data confirm that ∼5% of patients with GPS do not have detectable levels of anti-GBM antibodies.

• Authors: Michael Mahler, Antonella Radice, Renato A Sinico, Jan Damoiseaux, Andrea Seaman, Kristen Buckmelter, Alenka Vizjak, Carol Buchner, Walter L Binder, Marvin J Fritzler, Zhao Cui
• Journal: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association (Nephrol Dial Transplant) Vol. 27 Issue 1 Pg. 243-52 (Jan 2012) ISSN: 1460-2385 [Electronic] England
• PMID: 21562146 (Publication Type: Comparative Study, Evaluation Study, Journal Article, Multicenter Study)

Chemical References

• Autoantibodies
• Collagen Type IV
• antiglomerular basement membrane antibody

Topics

• Anti-Glomerular Basement Membrane Disease (diagnosis, immunology)
• Autoantibodies (blood, immunology)
• Case-Control Studies
• Collagen Type IV (immunology)
• Glomerular Basement Membrane (immunology)
• Humans
• Immunoassay (methods)
• International Agencies
• Luminescent Measurements (methods)
• Prognosis
• Sensitivity and Specificity