Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Medicine, General & Internal, General & Internal Medicine

Abstract:

Introduction .– Anti-PR3 antibodies represent an established and widely applied marker for the diagnosis of small vessel vasculitis, such as granulomatosis with polyangitis (GPA). This multi-center study was designed to critically analyze the performance of QUANTA Flash PR3, a chemiluminescent immunoassay (CIA) on a random access rapid response (30min) auto-analyzer for the detection of anti-PR3 antibodies, by testing a large number of samples from multiple clinical sites, selected samples in comparison to EliA PR3s (Thermo Scientific). Methods .– Sera from 292 GPA patients and other diseases (n =1356) were collected from 11 different laboratories in multiple countries (Germany, Italy, The Netherlands, Slovenia, France, Canada, Belgium, Poland, Austria) and tested by QUANTA Flash PR3. A total of 196 samples from two sites were also tested by EliA PR3S. Results .– Clinical sensitivity and specificity for QUANTA Flash among all patients (n =1648) were 62.7% (95% CI 56.8–68.2%) and 98.0% (95% CI 97.1–98.7%), respectively. Among the samples run on both QUANTA Flash and ELiAs (n =196), the discriminations between GPA patients and controls were similar: 56.1% (95% CI 44.7–67.0%)/98.2% (95% CI 93.8–99.8%) sensitivity/specificity for QUANTA Flash and 58.5% (95% CI 47.1–69.3%)/96.5% (91.3–99.0%) sensitivity/specificity for ELiAs. In addition, good agreements were found between assays: 86.5% (95% CI 74.2–94.4%) positive agreement, 97.9% (95% CI 94.0–99.6%) negative agreement and 94.9% (95% CI 90.8–97.5%) overall agreement. Spearman’s rho was 0.74 (95% CI 0.67–0.80). Discussion .– Large multi-centric studies are important to evaluate the performance of novel diagnostic assays. In our study with samples from various countries, we found good performance characteristics of QUANTA Flash CIA and good agreement with EliAs. Conclusion .– With the availability of QUANTA-Flash PR3 CIA the detection of anti-PR3 antibodies can now be performed with high reliability in clinical settings where rapid turnaround times (30minutes) are important.