| Objective: To investigate the interference of rheumatoid factor(RF)in patients’ serum on the detection of anti-double-stranded DNA(ds-DNA)antibody by indirect immunofluorescence method(IIF)and the effect of three methods to eliminate this interference.Since anti-DS-DNA antibody is almost exclusively found in the sera of patients with systemic lupus erythematosus(SLE),it is a serological marker and specific antibody for SLE.At the same time,it was found that RF would interfere with the detection of anti-DS-DNA antibody.Therefore,this experiment was conducted by collecting serum from patients whose RF was significantly higher than the normal reference value range(< 14.00 IU/ml)and false positive non-specific fluorescence model was observed under fluorescence microscope.To explore the interference caused by high concentration of RF in the serum of patients on the detection of anti-DS-DNA antibody by IIF method.At the same time,three methods were adopted to eliminate the interference and observe the effect of removing the interference.Materials and methods: In this study,a total of 631 patients with anti-DS-DNA antibody samples tested by IIF method were selected from our hospital from September2021 to June 2022,and 10 patients with false positive serum samples were selected as subjects of this study.The RF removal experiments were carried out by three methods:fetal bovine serum,PEG 6000 and rheumatoid factor latex particles.The treated serum was again detected by the anti-DS-DNA antibody IIF method and RF concentration detection.Collect and sort experimental data for statistical analysis.Results: The original concentration of RF in serum of the 10 patients was higher than the normal reference range(< 14.00 IU/ml).The RF concentration was significantly decreased by fetal bovine serum,PEG 6000 and rheumatoid factor latex particles,and the average decrease rate of RF removal by fetal bovine serum was41.29%.The average reduction rate of RF removal by PEG 6000 was 81.48%.The average reduction rate of RF removal by rheumatoid factor emulsion particles was81.43%.The reduction of RF by PEG 6000 and rheumatoid factor latex particles was similar,while the reduction of RF by fetal bovine serum was about half of the above two methods.At the same time,it was observed that the false positive nonspecific fluorescence model disappeared after the removal of RF by three methods.Conclusion: It was confirmed that the presence of RF interfered with the detection of anti-DS-DNA antibody by IIF method,which could make anti-DS-DNA antibody show false positive non-specific fluorescence model under fluorescence microscope.The three methods adopted in this experiment can successfully reduce RF concentration and eliminate interference.The removal of RF by PEG 6000 and rheumatoid factor latex particles was better than that by fetal bovine serum.The false positive fluorescence model under fluorescence microscope was restored negative by removing RF.This method can be used as an auxiliary diagnostic method for difficult clinical cases.It can be used as a reference for the treatment of false positive cases of anti-DS-DNA antibody detected by IIF method.In addition,this method is recommended because it has the advantages of cheap price,simple operation method and good interference removal effect. |
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