Background: Urgent clinician notification of low hemoglobin values is a common practice. The effect of such notification for samples obtained during an office visit is uncertain. Methods: We notified the attending physicians in 100 consecutive cases of outpatients with hemoglobin <80 g/L. We reviewed the medical charts of these patients with their personal physicians 1-2 months later. We considered transfusions unnecessary only when given to a clinically stable patient with probable iron deficiency anemia in the absence of chronic diseases that produce the anemia. Results: Overall, 47 (47%) of the patients were referred to the emergency room (ER), and 31 of the 47 (66%) were transfused. Increasing age and decreasing hemoglobin were associated with increased referral of patients to the ER. Six of 31 transfusions were unnecessary. An emergency transfusion was clearly indicated in only 3 of the 31 patients; the other patients were clinically stable. A modified notification strategy excluding microcytic samples >50 g/L would have detected these three patients. Over the follow-up period, no patient not referred to the ER died from complications of anemia, nor were any patients hospitalized with acute symptoms of low hemoglobin. Conclusion: In some settings, urgent notification of medical outpatient clinics of patients with hemoglobin <80 g/L may lead to unnecessary ER visits.