Comparison of quantitative and qualitative anti-dsDNA assays

Area of Science:

• Immunology
• Clinical Chemistry
• Rheumatology

Background:

• Anti-double-stranded DNA (anti-dsDNA) antibodies are crucial biomarkers for diagnosing and monitoring systemic lupus erythematosus (SLE).
• Recent advancements have introduced new methods for anti-dsDNA assessment, but their performance and limitations require thorough evaluation.

Purpose of the Study:

• To compare the performance and concordance of recently developed anti-dsDNA antibody assays.
• To evaluate the clinical utility of different anti-dsDNA testing methods in SLE patient samples.

Main Methods:

• Analyzed 129 antinuclear antibody testing specimens across 4 US medical centers.
• Compared five anti-dsDNA assays: Werfen Quanta Lite dsDNA, Zeus Scientific dsDNA EIA, Bio-Rad MIA dsDNA, ImmunoConcepts Crithidia, and Bio-Rad Crithidia.

Main Results:

• Zeus and Werfen quantitative assays showed the highest correlation (ρ = 0.86).
• Multiplex immunoassay (MIA) showed moderate correlation with quantitative assays (ρ ≈ 0.58-0.59).
• Positive concordance varied widely (31.4%–97.1%), while negative concordance was high (58.5%–100%). Detection rates in SLE patients differed significantly between quantitative (50.9%–77.4%) and Crithidia assays (15.1%–24.5%).

Conclusions:

• Current quantitative anti-dsDNA assays are not interchangeable for consistent patient monitoring in SLE.
• Crithidia-based assays exhibit high negative concordance but lack positive concordance, indicating limited utility for confirming disease activity.