Figure 4. Changes in indirect immunofluorescence-antineutrophil cytoplasmic antibodies (IIF-ANCA) titers using the standard and improved IIF techniques. The median IIF-ANCA titers among positive tests increased from 1/40 (1/30-1/160) to 1/80 (1/40-1/80) using the standard and the improved IIF techniques, respectively. Data were analyzed with the Wilcoxon signed-rank test.
