Abstract Background Sepsis is caused by bacteria infected in the bloodstream and the body’s inability to control inflammation. Procalcitonin (PCT) is a biomarker of infection in patients with sepsis, the severity of the infection, and whether the patient is responding to therapy. Thus, diagnostics and early treatment are very important for doctors and patients. In a hospital concerned with sepsis in patients, a doctor ordered a PCT level and hemoculture before treating an antibiotic on a patient whose doctor suspects sepsis. The objective of this study is to compare the PCT level in the blood and hemoculture results in patients. Methods In this study, we evaluated the patients who suspected sepsis disease and were admitted to the Uttaradit Hospital, Thailand, between October 2022 and October 2023. The patients were divided into two groups: those with positive hemoculture results (sepsis group) and those with negative hemoculture results (non-sepsis group). The PCT levels in the blood were measured on Alinity ci analyzers and compared between the two groups to determine if there was a significant difference. Additionally, clinical data such as age and gender were collected to assess their potential impact on PCT levels and hemoculture results. Results The results of the study showed that the sepsis group had significantly higher PCT levels compared to the non-sepsis group. And the difference in PCT levels between the sepsis and non-sepsis groups was considerably more marked for patients older than 60. Furthermore, there was no significant difference in PCT levels based on gender in either group. Conclusions This finding suggests that measuring PCT levels could potentially serve as a diagnostic tool for identifying sepsis in patients. A patient age may be a contributing factor to the severity of sepsis and could potentially be used as a marker for early detection and intervention in older patients. Further research is needed to validate these results and explore the clinical implications of using PCT as a biomarker for sepsis diagnosis.