Vancevska, Aleksandra (55812981100)Aleksandra (55812981100)VancevskaNikolic, Aleksandra (57194842918)Aleksandra (57194842918)NikolicBonaci-Nikolic, Branka (10839652200)Branka (10839652200)Bonaci-NikolicSkiljevic, Dusan (23487265400)Dusan (23487265400)SkiljevicRadojkovic, Dragica (6602844151)Dragica (6602844151)Radojkovic2025-07-022025-07-022016https://doi.org/10.1002/jcla.21939https://www.scopus.com/inward/record.uri?eid=2-s2.0-84963568766&doi=10.1002%2fjcla.21939&partnerID=40&md5=468e1b8128850790ecda518e6807f088https://remedy.med.bg.ac.rs/handle/123456789/13266Background: We report the improvement of previously described method for determining deoxyribonuclease (DNase) activity in serum samples that uses a fluorescently labeled DNA fragment as a substrate. Methods: Activity of serum DNase was analyzed in 31 patients with systemic lupus erythematosus (SLE) and 13 healthy individuals by fluoresence-based method and ELISA test. Results: We found a mean decrease in DNase activity between cases and controls of 12.46% measured by the fluoresence-based method and of 12.21% measured by ELISA method. High level of positive correlation between two methods for DNase activity was observed: P < 0.001 and Pearson correlation coefficient 0.740. Decreased DNase activity was found in 25 of 31 SLE patients (81%) by fluoresence-based method and in 24 of 31 SLE patients (77%) by ELISA test. We also observed the significant positive correlation between titer of anti-dsDNA antibodies and DNase activity measured by both methods (P < 0.05). Conclusions: The key improvement is the use of internal control in the fluorescence-based method, which diminishes the influence of technical errors on the obtained results and increases reliability of the assay. This improved fluorescence-based method, with additional validation, may provide an alternative to more expensive and time-consuming conventional methods, such as ELISA. © 2016 Wiley Periodicals, Inc.deoxyribonuclease activityELISAfluorescencesystemic lupus erythematosus