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Goals: The existence of anti-dense fine speckled (DFS) 70 autoantibodies are considered an exclusionary biomarker for systemic autoimmune rheumatic diseases (SARDs). Several tests to confirm the presence of anti-DFS70 autoantibodies have been introduced, and the use of them in specimens with a DFS pattern in indirect immunofluorescence-antinuclear antibody (IIF-ANA) testing has been suggested. However, these additional tests have only been evaluated in a small number of samples; their clinical usefulness therefore requires further evaluation., Methods: A total of 213 serum specimens showing DFS (n=155) or homogeneous (H; n=58) patterns were included. All specimens were tested by western blotting (WB) and enzyme immunoassay (EIA). Clinical information regarding SARDs was analyzed., Results: The detection rates for WB and EIA for anti-DFS70 autoantibodies in specimens with a DFS pattern were 86.5% and 73.5%, respectively. Detection rates in specimens with a low IIF-ANA titer were significantly lower than those in specimens with a high titer. The detection rate of anti-DFS70 autoantibodies in 58 specimens with an H pattern was 10.3% (6/58). Among 155 subjects with a DFS pattern in IIF-ANA staining, only five were diagnosed with SARD., Conclusions: There is little need to confirm the presence of anti-DFS70 autoantibodies using other methods. When a DFS pattern is observed in IIF-ANA staining, it is more important to confirm the presence of other autoantibodies related to SARDs than to identify anti-DFS70 autoantibodies. Finally, more careful interpretation of IIF-ANA to specimens with a low IIF-ANA titer is needed., (© 2019 by the Association of Clinical Scientists, Inc.)

Background: Clostridium difficile is one of the most common causes of nosocomial diarrhea, and diagnostic methods for detecting C. difficile infection have shifted from conventional to more recent molecular techniques. This study aimed to compare the performance of two molecular assays (Meridian Illumigene™ and AdvanSure CD real-time PCR) in detecting C. difficile using a toxigenic culture as a reference standard., Materials and Methods: This study was conducted at Kyung Hee University Hospital, a tertiary university teaching hospital in Seoul, Korea, from July 2010 to February 2011. The study used 203 fresh diarrheal stools. All fecal specimens were immediately tested by culture and the VIDAS C. difficile toxin A & B assay using an automated VIDAS immunoanalyzer. The remainder was stored at -70°C until required for AdvanSure CD real-time polymerase chain reaction and Illumigene™. The alcohol shock procedure was then performed. Aliquots were inoculated directly on C. difficile-selective agar and blood agar and then incubated in an anaerobic jar for 48 h at 35°C. The Rapid ID 32 A test was used for specifying colonies on plates. The AdvanSure CD real-time PCR was used to detect the tcdA and tcdB gene, and PCR Illumigene™ kits were used to detect the tcdA gene of the pathogenicity locus (PaLoc) harboring toxigenic C. difficile., Results: Of 203 clinical samples, 197 showed identical results between the two molecular assays, with a concordance rate of 97.0%. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were as follows: Illumigene: 92.3, 99.4, 96.0, and 98.9, respectively; AdvanSure CD real-time PCR: 84.6, 98.3, 88.0, and 97.8, respectively., Conclusions: Both molecular assays demonstrated good sensitivity and specificity. Additionally, both molecular assays showed comparable results to those of a toxigenic culture, albeit with a slight decrease in test sensitivity and specificity.

Background: Although the method of choice to detect M-protein is electrophoresis on an agarose gel, such gel electrophoresis (GE) is labor-intensive, time-consuming, and not standardized. In contrast to GE, capillary electrophoresis (CE) has some merits because it is automated, fast, and highly reproducible. However, CE results occasionally make the interpretation difficult and require additional confirmatory tests like GE., Methods: In order to assist a correct reporting of CE results and compatible interpretations between two different electrophoresis methods, we report here two unusual cases of monoclonal gammopathy by a pattern of polyclonal gammopathy upon CE interpretation in patients with end stage renal disease and multiple myeloma., Results: In these cases, serum CE showed the broad bumpy peak in the gamma region. This bumpy peak does not drop completely flat after the reaction with anti-FLC., Conclusions: Because the plasma cell is a B-cell lineage and plays an important role in adaptive immunity, MG accompanying with PG is not rarely found in plasma cell dyscrasia. If the broad bumpy peak is observed in CE, careful examinations must be done to rule out the hidden M-peak. In our cases, a parallel use of gel-based methods was very helpful as it revealed monoclonal bands.