Using conventional methods, organism identification (ID) and antibiotic susceptibility testing (AST) results are available ∼1.5-3 days after positive blood culture. New technologies can reduce this time to 8-12 h, allowing therapy to be optimized substantially sooner. To make full use of fast ID and AST results requires overcoming various hurdles to effective implementation, including restructuring laboratory workflows to optimize timeliness of results and modifying clinical pathways to respond more quickly when results are available. Efficient laboratory procedures and clinical interventions coupled with fast and accurate identification and AST results have the potential to substantially reduce overall costs and provide more-sophisticated and effective patient management.