ABSTRACT
Many laboratories do not test antinuclear antibodies [ANA] by indirect immune-fluorescence [IIF] in parallel with anti-double stranded [ds] DNA antibodies. This study attempts to investigate the legitimacy of such practice. A retrospective laboratory data analysis of simultaneous assessment of ANA and anti-dsDNA antibody results of 106 patients with either diagnosed or suspected systemic lupus erythematosus [SLE] was performed at King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia. The ANA was detected by IIF on HEp2 cells and anti-dsDNA antibodies were assessed by specific ELISA test. Among the patients, female preponderance [96.3%] was evident and a coarse speckled fluorescence pattern was commonly observed [60.4%]. There was almost no detection of anti-dsDNA antibodies up to an ANA titer of 1:320. Anti-dsDNA antibodies were often detected at ANA titers of 1:640 and beyond. Other patterns of fluorescence observed at ANA titers as low as 1:40 and at higher dilutions were, fine speckled [14.15%], homogeneous [9.4%], anti-mitochondrial [7.5%], ribosomal [4.7%], and nucleolar [3.8%]. Linear regression analysis revealed a statistically significant relationship [p=0.02] between ANA titers and anti-dsDNA antibodies only in the presence of a coarse speckled pattern. The rare occurrence of anti-dsDNA antibodies at clinically significant ANA titers associated with the coarse speckled pattern may mask the diagnosis of SLE. Similarly, the diagnosis of SLE may be overlooked if anti-dsDNA antibodies are not checked in the presence of clinically insignificant ANA titers associated with other patterns of fluorescence