Optimizing Red Blood Cell Transfusion Thresholds Across Medical, Surgical, and Obstetric Populations: A Systematic Review

Abstract

Red blood cell (RBC) transfusion remains a cornerstone of supportive care across medical, surgical, and obstetric settings; however, the optimal hemoglobin threshold for transfusion continues to be debated due to concerns regarding transfusion-related complications, resource utilization, and patient outcomes. This systematic review aimed to evaluate the efficacy and safety of restrictive versus liberal RBC transfusion strategies across diverse adult patient populations. A comprehensive literature search of PubMed/MEDLINE, Embase, Scopus, Web of Science, Cochrane Library, and ClinicalTrials.gov was conducted from database inception through June 2026 in accordance with PRISMA 2020 guidelines. Studies comparing restrictive transfusion thresholds (typically 7–8 g/dL) with liberal thresholds (typically 9–10 g/dL) were included. A total of 97 studies involving more than 350,000 patients were analyzed. Across critically ill patients, septic shock, gastrointestinal bleeding, orthopedic surgery, and cardiac surgery populations, restrictive transfusion strategies consistently reduced blood product utilization without increasing mortality, cardiovascular complications, infection rates, length of hospital stay, or other major adverse outcomes. In patients with acute gastrointestinal bleeding, restrictive transfusion was associated with improved survival and lower rebleeding rates. Evidence from obstetric populations suggested similar maternal outcomes with reduced transfusion exposure, although data were less robust than those available for medical and surgical cohorts. Uncertainty persists in selected high-risk populations, including patients with acute coronary syndromes, severe cardiovascular disease, and major obstetric hemorrhage, where individualized clinical assessment remains essential. Overall, current evidence strongly supports restrictive RBC transfusion strategies as a safe, effective, and resource-efficient approach for most hemodynamically stable adult patients, reinforcing contemporary patient blood management principles and the need to minimize unnecessary transfusion exposure while maintaining optimal clinical outcomes.