Comparative evaluation of two MALDI-TOF MS systems for microbial identification: accuracy and workflow efficiency in a clinical microbiology laboratory.

This study aimed to compare the identification accuracy and workflow of the VITEK MS PRIME (VMP) and the MALDI Biotyper Sirius (BS) in a routine laboratory setting. A total of 927 isolates, representing 219 different species, were analyzed using both the VMP and the BS system. In addition, 119 positive blood cultures were tested after 4-6 h of subculture, with and without formic acid, and compared to the results obtained after 18 to 24 h. Hands-on time (HOT) and time to result (TTR) were measured based on a workflow consisting of 16 slides, each containing 16 isolates, with a total of 256 isolates, simulating the daily workload of a single technician. Of the 927 isolates tested, both systems demonstrated high identification rates (91.1% for BS and 95.5% for VMP). Agreement between the two matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) instruments after retesting was 99.4% and 97.5% at genus and species levels. In short-incubation cultures, VMP identified 118 (99.2%) isolates without and 113 (95.0%) with formic acid treatment, while BS identified 105 (88.2%) and 110 (92.4%), respectively. Workflow analysis demonstrated a HOT of 106 min and a TTR of 191 min for VMP with 252 successful identifications (98%). In contrast, BS required 155 min for both HOT and TTR, yielding 211 successful identifications (82%). Both MALDI-TOF systems evaluated in this study demonstrated an excellent concordance in the identification of a broad range of species. Depending on the laboratory settings, either system is well-suited to support an efficient and streamlined laboratory workflow. IMPORTANCE: This study provides a real-world comparison of two leading matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems, VITEK MS PRIME (VMP) and MALDI Biotyper Sirius (BS), based on 927 isolates across 219 species, including rare and challenging organisms. By simulating routine lab workflows working with several workstations, it offers practical insights into hands-on time and time to results. Unlike previous studies, it includes a broader sample set (including yeasts), evaluates short positive blood culture incubation conditions, and accounts for operator variability. These strengths make it a valuable resource for laboratories seeking evidence-based guidance on MALDI-TOF implementation and optimization.