Diagnosing Iron Deficiency Anemia Preoperatively

Preoperative anemia is associated with an increased chance of perioperative morbidity and mortality [1]. This is true across a variety of surgeries: anemia can jeopardize the long-term outcome of patients undergoing cardiovascular or non-cardiovascular operations [2, 3]. Of the various conditions that cause perioperative anemia, iron deficiency is very common [1]. If diagnosed about a month before surgery, iron deficiency can be treated successfully [4]. Unfortunately, iron deficiency is frequently undiagnosed, with potentially fatal implications for this patient [1]. This article discusses two means of diagnosing iron deficiency anemia, as well as the steps medical professionals can take after diagnosis to improve surgical outcomes. 

The most common technique of diagnosing iron deficiency anemia is by obtaining the patient’s complete blood count [1]. Following a diagnosis of anemia, a patient must return to the laboratory to give further blood samples and be tested for various metrics, including thyroid function, iron studies, and reticulocyte count [1]. With these tests, physicians will be able to diagnose the type of anemia that patients suffer from [1]. Although these tests can help diagnose some iron deficiency anemia cases, their accuracy can be limited [1]. 

In response to the limitations of the traditional method, researchers offered an alternative approach, consisting of a complete blood count followed by reflex anemia testing in patients with a hemoglobin concentration less than or equal to 12 g/dl [1]. Reflex testing is an automated process that can diagnose iron deficiency anemia and the most common medical conditions that cause anemia [1]. The process would only require a single patient visit and can be more cost-effective [1]. Compared to the traditional method, which diagnosed 1.2 and 3.3% of patients at two different stages, this two-step process diagnosed 26.1% of patients with anemia during the study, suggesting that it can diagnose iron-deficiency anemia more efficiently and effectively [1]. 

If a timely diagnosis of iron deficiency anemia can be achieved, patients can be treated before surgery to prevent complications. Effective treatment can prevent patients from needing perioperative red cell transfusions, which run the risk of perioperative and postoperative complications [4, 5]. One means of treating anemia is iron infusion therapy (IVI), which should occur 22 to 28 days before surgery to maximize efficacy [1]. Studies have shown IVI to be of minimal risk and successful in preventing perioperative anemia-related complications when treating colorectal cancer, gynecology, and obstetric patients [4, 6]. Even if a medical team decides against IVI, research suggests that referring patients to a structured preoperative anemia management clinic lowers the chance that they will need a blood transfusion later on [5]. 

Even if the alternatives to traditional complete blood counting are not extensive, it is clear that physicians must take the steps to diagnose their patients’ iron deficiency anemia before surgery. Given the independent predictive power of anemia in determining several surgical outcomes, this is a condition that cannot be taken lightly, especially given the potential benefit of preoperative testing and proactive treatment [2]. 


[1] O. Okocha et al., “An Effective and Efficient Testing Protocol for Diagnosing Iron-deficiency Anemia Preoperatively,” Anesthesiology, vol. 133, no. 1, p. 109-118, July 2020. [Online]. Available:

[2] M. Dunkelgrun et al., “Anemia as an Independent Predictor of Perioperative and Long-Term Cardiovascular Outcome in Patients Scheduled for Elective Vascular Surgery,” The American Journal of Cardiology, vol. 101, no. 8, p. 1196-1200, April 2008. [Online]. Available:

[3] K. M. Musallam et al., “Preoperative Anaemia and Postoperative Outcomes in Non-Cardiac Surgery: A Retrospective Cohort Study,” The Lancet, vol. 378, no. 9800, p. 1396-1407, October 2011. [Online]. Available:

[4] I. Ellermann et al., “Treating Anemia in the Preanesthesia Assessment Clinic: Results of a Retrospective Evaluation,” Anesthesia & Analgesia, vol. 127, no. 5, p. 1202-1210, November 2018. [Online]. Available:

[5] U. S. Perepu, A. M. Leitch, and S. Reddy, “Implementation of a Preoperative Anemia Management Clinic in a Tertiary Academic Medical Center,” Blood, vol. 128, no. 22, p. 1004, December 2016. [Online]. Available:

[6] M. Muñoz et al., “Perioperative Anemia Management in Colorectal Cancer Patients: A Pragmatic Approach,” The World Journal of Gastroenterology, vol. 20, no. 8, p. 1972-1985, February 2014. [Online]. Available: