What is the initial management of a patient with low hemoglobin (Hb) presenting to the Emergency Department (ED) from a Primary Care Physician (PCP)?

Initial Management of Low Hemoglobin in the Emergency Department

Immediately assess hemodynamic stability and obtain vital signs within 10 minutes of arrival, establish IV access, draw baseline labs including CBC with differential, reticulocyte count, iron studies (ferritin, transferrin saturation, TIBC), and peripheral blood smear, while simultaneously evaluating for active bleeding or hemolysis. 1

Immediate Stabilization and Assessment

Primary Survey (First 10 Minutes)

• Check airway patency, oxygen saturation via pulse oximetry, and administer supplemental oxygen if hypoxemic 1
• Establish IV access immediately and obtain blood samples for baseline studies including CBC, reticulocyte count, iron panel (ferritin, transferrin saturation), peripheral smear, and type and screen 1, 2
• Measure blood pressure and assess for signs of poor perfusion (tachycardia, hypotension, altered mental status) 1
• Check blood glucose in all patients, especially those with altered mental status 1

Critical Clinical History Points

• Determine exact timing and acuity of symptom onset - acute versus chronic presentation fundamentally changes management 2, 3
• Assess for active bleeding sources: gastrointestinal (melena, hematochezia, hematemesis), menstrual (menometrorrhagia in women of reproductive age), or occult bleeding 4, 5
• Evaluate symptoms of acute anemia: chest pain, dyspnea, lightheadedness, syncope 2
• Evaluate symptoms of chronic anemia: progressive fatigue, exercise intolerance, pica, restless legs 2, 4

Diagnostic Workup Based on Hemoglobin Level

Hemoglobin < 7 g/dL (Critical)

• Consider immediate red blood cell transfusion if hemodynamically unstable or symptomatic (chest pain, dyspnea, altered mental status) 5
• Transfuse 1-2 units of packed red blood cells and reassess 5
• Note that hemoglobin level is the main determinant for transfusion in the ED, not just symptoms alone 5
• Even patients with remarkably low hemoglobin (as low as 1.4 g/dL) can present hemodynamically stable if chronic compensation has occurred, but this is exceptional 4

Hemoglobin 7-10 g/dL (Moderate)

• Transfusion decision depends on symptoms, comorbidities (cardiac disease), and clinical stability 2, 5
• For iron deficiency anemia, IV iron is preferred over transfusion when patient is hemodynamically stable, as it increases hemoglobin rapidly and durably 5
• Most patients with chronic anemia in this range may be discharged with close follow-up if hemodynamically stable 2

Hemoglobin > 10 g/dL (Mild)

• Rarely requires transfusion unless symptomatic or acute blood loss 2
• Outpatient management with oral iron supplementation (ferrous sulfate 1 tablet 2-3 times daily) for iron deficiency 6

Classification by Mean Corpuscular Volume (MCV)

Microcytic Anemia (MCV < 80 fL)

• Most commonly iron deficiency anemia - check ferritin < 30 µmol/L and transferrin saturation < 20% 5
• For confirmed iron deficiency with hemodynamic stability, prescribe IV iron (preferred) or oral iron supplementation 5, 6
• Consider thalassemia trait, anemia of chronic disease, or sideroblastic anemia in differential 7, 3

Normocytic Anemia (MCV 80-100 fL)

• Check reticulocyte count to differentiate decreased production versus increased destruction/loss 7, 3
• Elevated reticulocyte count suggests hemolysis or acute blood loss 3
• Low reticulocyte count suggests bone marrow suppression, chronic kidney disease, or anemia of chronic disease 7

Macrocytic Anemia (MCV > 100 fL)

• Consider B12/folate deficiency, alcohol use, liver disease, hypothyroidism, or myelodysplastic syndrome 7, 3
• Check B12, folate, TSH, and liver function tests 3

Common Pitfalls to Avoid

• Do not delay assessment beyond 10 minutes of arrival 1
• Do not fail to check blood glucose in patients with altered mental status 1
• Iron deficiency is severely underinvestigated - iron studies are only ordered in 10.3% of anemic ED patients despite being present in 5.1% 5
• IV iron is vastly underutilized - only 1.5% of iron-deficient patients receive IV iron despite its superiority over transfusion for stable patients 5
• Do not transfuse stable patients with chronic iron deficiency anemia - IV iron is the preferred treatment 5
• Ferritin > 100 µmol/L excludes iron deficiency anemia 5

Disposition Decision

Admit if:

• Hemodynamically unstable despite resuscitation 2
• Active ongoing bleeding requiring intervention 2
• Hemoglobin < 7 g/dL with symptoms 5
• Significant cardiac symptoms (chest pain, dyspnea) 2

Discharge with Close Follow-up if:

• Hemodynamically stable 2
• Chronic anemia with identified cause 2
• Hemoglobin > 7 g/dL without symptoms 2
• Arrange outpatient hematology or primary care follow-up within 1-2 weeks 2
• Prescribe oral iron supplementation for confirmed iron deficiency 6