Comparison of the Abbott Architect BRAHMS and the Biomérieux Vidas BRAHMS Procalcitonin Assays

Background Procalcitonin (PCT) is a well-established marker for bacterial infection. Recently the US Food and Drug Administration approved the expanded use of this biomarker to guide clinical decisions for antibiotic treatment in patients with lower respiratory tract infections. Both the Architect BRAHMS PCT (PCT-A) and Vidas BRAHMS PCT (PCT-V) are approved for this indication. The aim of this study is to evaluate analytical performance of PCT-A in comparison to PCT-V. Methods PCT-A and PCT-V were evaluated for intra- and interassay precision and functional sensitivity. To assess the accuracy of PCT-A, 108 residual plasma specimens were randomly selected from routine hospital orders, and PCT was measured concurrently with PCT-A and PCT-V. Results Both assays demonstrated excellent precision, with intraassay precision ranging from 2.2% to 4.0% CV and interassay precision ranging from 2.5% to 3.6% CV. The functional sensitivity was verified at 0.01 ng/mL for PCT-A and at 0.05 ng/mL for PCT-V. The Passing–Bablok regression revealed approximately 20% negative bias of PCT-A compared to PCT-V (PCT-A = 0.042 + 0.79 × PCT-V, r = 0.995). The concordance of the 2 methods at diagnostically important cutoffs (0.10, 0.25, 0.50, and 2.0 ng/mL) was excellent, with overall agreement >93% at each threshold. Conclusion The results of our study show improved sensitivity and equivalent clinical performance of PCT-A compared to PCT-V. The availability of this test on common clinical immunoassay analyzers may help accelerate its adoption into antimicrobial stewardship programs and thereby improve antibiotic use and patient outcomes.