"Detect Anemia Preoperatively": A Scoping Review of Recommendations.

Background: Preoperative anemia significantly impacts patient outcomes, prompting increasing global implementation of patient blood management (PBM) measures. Timely diagnosis and differentiation of preoperative anemia are crucial components of PBM to maximize its effectiveness. Despite this, comprehensive implementation remains inconsistent. This scoping review aims to give an overview of recommendations regarding preoperative anemia management to detect gaps in knowledge and emerging ideas. Methods: A scoping review, adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, investigated preoperative anemia detection, focusing on patient population, timing, extent, and process of investigations. PubMed and ScienceDirect were searched for English and German articles published in the last 5 years, supplemented by manual selection. Pediatric and obstetric recommendations were excluded. Results were synthesized based on key questions. Results: Four hundred sixty-five articles were screened, and 80 met the inclusion criteria, including 25 clinical practice guidelines. Most (n = 62) suggested "detect and correct" anemia without further specification. The rest advised conducting investigations early, ideally up to 30 days before major procedures with expected blood loss >500 mL. Recommended tests include blood counts, various iron parameters, folic acid/vitamin B12, inflammation markers, and renal, hepatic, and thyroid function tests. Ten articles described detailed algorithms. Other key recommendations included using reticulocyte hemoglobin, point-of-care Hb measurements, and automated laboratory algorithms. The underlying quality of scientific evidence is heterogeneous. Conclusions: International recommendations on the detection of preoperative anemia are heterogeneous and often generic. Automated algorithms could make a significant contribution to practicability. While practice-oriented guidelines, especially by surgical societies, could promote standardized and efficient implementation, further research is needed to improve the quality of underlying scientific evidence.