Although there are many processing nuances to consider when designing a laboratory workflow around the MALDI-TOF MS, these can generally be broken down into two main categories—centralized and decentralized processing.
Centralized Processing
The centralized approach to processing MALDI-TOF MS will rely on a single station for the processing of target plates. This workflow will be very similar to the way many laboratories already batch process antimicrobial susceptibility testing (AST). As such, laboratories may elect to incorporate the MALDI-TOF MS set-up into a particular bench. Bench reading scientists bring the agar plates to the MALDI-TOF MS bench and the assigned individual will spot and perform the microorganism identification. With this workflow, laboratories must have protocols in place that allow the bench scientist to indicate which isolates are to be tested. This requires specific identification of which colonies will be worked up (e.g., colonies being circled with a marker or a wax pencil).
Alternatively, in semi-batch mode, laboratories can distribute target plates to each bench and have the scientists spot their own targets. Once these tests are spotted, they can be brought to a dedicated individual who will pipette the reagents and process the targets; this work may be advantageous in avoiding errors in selecting microorganisms for identification. In either case, accountability for accuracy in target location of individual organisms is critical. The previously mentioned tracking systems improve this process.
Decentralized Processing
The decentralized approach dictates that each scientist be responsible for the entire MALDI-TOF process. As discussed previously, this approach requires that many individuals be trained and rendered competent in performing the MALDI-TOF MS procedures. The major advantage of this workflow is accountability in that a single scientist oversees all steps of identification and correlates these with AST.
The major disadvantage of this approach is that bottlenecks may occur in competition for processing target plates. MALDI-TOF MS instruments are not designed for random access and the speed in turn-around becomes a critical issue in this type of workflow.
