Objective Inappropriate antibiotic treatment can significantly affect antimicrobial resistance, resulting in treatments becoming less effective in the future. Previous studies have not identified the possible de-escalation rate. The aim of this study was to assess the appropriateness of antibiotic treatment in patients who have a blood culture collected, in particular, calculating how many days of antibiotics can be de-escalated. Methods A patient series, observational study was conducted that included all patient blood culture, regardless of whether they were positive or negative, over a period of 4 days. The study was repeated three times to attain a larger sample. The adequacy of antibiotic treatment was determined based on microbiology results, prescription drug administration, and patient notes/charts. Results Of the 69 suitable cases, 36 (52.17%) received appropriate treatment and 33 (47.83%) received inappropriate treatment. Of the inappropriate cases, it was calculated that 83 days of de-escalation were possible. Fifteen (21%) of the cases could have de-escalated use of meropenem. Conclusion The results highlight that there is opportunity to review and de-escalate patient's treatment, after taking a blood culture and practices such as rationalizing antibiotic choices and educating physicians on reviewing antibiotics is appropriate.