Blood cultures play an essential role in the diagnosis and management of bloodstream infections. Rapid microbial identification and antimicrobial susceptibility testing (AST) provide crucial information for patient management. Traditionally, a positive blood culture broth is inoculated onto appropriate agar media. The agar is incubated for 18-24 hours before performing microbial identification and AST. However, this may lead to delayed intervention in the treatment for patients with bloodstream infections. A study into rapid alternatives for preliminary pathogen identification and AST was conducted. Microbial identification was done using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and AST using the calibrated dichotomous susceptibility (CDS) method. The study had two parts. Part A compared AST results from blood culture bottles via an inoculation step in nutrient broth, against mature bacterial cultures. Part B compared AST results between young same-day bacterial cultures and mature bacterial cultures. A total of 60 isolates, 30 in each study part, were tested from clinical positive blood cultures. The isolates consisted of common gram-negative (e.g., Enterobacterales), and gram-positive bacteria (e.g., Staphylococcus and Streptococcus species). In Parts A and B, 29 of 30 (97%) results were concordant, respectively. Discordant results occurred with fastidious microorganisms, which required extended incubation. Since this study targeted common pathogens from positive blood cultures, its findings may not be extended to unusual pathogens. Similarly, same-day testing and early microbial identification are not feasible when more than one pathogen is contained in blood cultures. However, in general, the early identification and AST produced reliable results. This can provide preliminary information for clinicians to make informed decisions about appropriate treatment. Further investigations should explore a broader range of pathogens, including slow-growing and fastidious microorganisms.