An effective and efficient testing protocol for diagnosing iron-deficiency anemia preoperatively

Background: Iron-deficiency anemia is a common perioperative condition and increases perioperative morbidity and mortality. Timely diagnosis and treatment are important. This retrospective cohort study tested the hypothesis that a newly developed preprocedure evaluation protocol diagnoses more patients with iron-deficiency anemia than the traditional practice of obtaining a complete blood count followed by iron studies. Methods: The preprocedure anemia evaluation is an order for a complete blood count and reflex anemia testing, which can be completed with a single patient visit. A hemoglobin concentration of 12 g/dl or less with serum ferritin concentration less than 30 ng/ml or transferrin saturation less than 20% defined iron-deficiency anemia. Northwestern Medicine's database was queried for preoperative clinic patients, age 16 to 89 yr, before (2015 to 2016) and after (2017 to 2018) protocol implementation. The proportion of patients diagnosed with iron-deficiency anemia before and after the preprocedure anemia evaluation implementation was compared. Results: Before implementing the protocol, 8,816 patients were screened with a traditional complete blood count. Subsequent iron studies at the providers' discretion diagnosed 107 (1.2%) patients with iron-deficiency anemia. Some patients were still screened with a complete blood count after implementing the protocol; 154 of 4,629 (3.3%) patients screened with a complete blood count and 738 of 2,828 (26.1%) patients screened with the preprocedure anemia evaluation were diagnosed with iron-deficiency anemia. The preprocedure anemia evaluation identified a far larger proportion of patients with iron-deficiency anemia than did the traditional complete blood count when compared both before (relative risk [95% CI], 21.5 (17.6 to 26.2); P < 0.0001) and after (7.8 [6.6 to 9.3]; P < 0.0001) its implementation. Conclusions: The preprocedure anemia evaluation improved identification of iron-deficiency anemia preoperatively. It is more effective and efficient, allowing anemia evaluation with a single patient visit.