Cytomegalovirus (CMV) infection is increasingly recognized in critically ill immunocompetent patients. Despite its high prevalence, the treatment of CMV in critical care is challenging due to diagnostic difficulties and drug toxicity. This indicates that developing a predictive model in critical care settings is promising for identifying patients at risk and initiating prophylactic therapy. Therefore, this case report presents a patient diagnosed with CMV infection based on CMV antigenemia, focusing on the appropriate timing for treatment.