ABSTRACT
Introduction:
The detection of anti-double-stranded (ds) deoxyribonucleic acid (DNA) antibodies is one of the classification criteria for diagnosing systemic lupus erythematosus (SLE).
Objective:
To describe a quantitative enzyme-linked immunosorbent assay (ELISA) for detecting anti-dsDNA immunoglobulin class G (IgG) antibodies.
Methods:
The performance of ELISA was evaluated using the Crithidia luciliae indirect immunofluorescence test (CLIFT) as a reference. Anti-dsDNA IgG antibodies were screened by ELISA and CLIFT in serum samples from 127 patients with SLE, 56 patients with other diseases and 37 healthy persons. The Cochran Q test was used to compare the sensitivity and specificity of the reactions, with differences among the results being considered significant when p ≤ 0.05.
Results:
ELISA had a sensitivity of 92.9% and a specificity of 94.6%, whereas the sensitivity and specificity of CLIFT were 85.8% and 100%, respectively. ELISA was significantly more sensitive than CLIFT (p = 0.0027), whereas CLIFT was significantly more specific than ELISA (p = 0.0253).
Conclusion:
ELISA showed excellent results in terms of sensitivity and specificity, with a potential use in research and routine diagnostics.
Key words:
systemic lupus erythematosus; antinuclear antibodies; enzyme-linked immunosorbent assay; indirect fluorescent antibody technique