What is the treatment for low Hemoglobin (Hb) and Hematocrit (Hct)?

Treatment of Low Hemoglobin and Hematocrit

The treatment approach depends critically on identifying the underlying cause, but for iron deficiency anemia—the most common etiology—oral iron supplementation at 60-120 mg/day of elemental iron for adults or 3 mg/kg/day for children is the first-line treatment, with reassessment after 4 weeks to confirm response (expected Hb rise ≥1 g/dL). 1, 2

Initial Diagnostic Confirmation

• Repeat the hemoglobin and hematocrit measurement to verify the initial screening result before initiating treatment 2
• Hemoglobin concentration is the more direct and sensitive measure compared to hematocrit, which only falls after hemoglobin decreases 2
• Evaluate iron status through ferritin and transferrin saturation (TSAT) to distinguish absolute iron deficiency (ferritin <100 ng/mL) from functional iron deficiency (ferritin >100 ng/mL with TSAT <20%) 1

Treatment Algorithm by Population

Adults (Non-Pregnant Women and Adolescent Girls)

• Prescribe oral iron 60-120 mg/day of elemental iron for confirmed iron deficiency anemia 1
• Administer iron between meals to maximize absorption 2
• Counsel patients about correcting iron deficiency through diet, emphasizing iron-rich foods and foods containing vitamin C to enhance absorption 1, 2
• Recheck hemoglobin after 4 weeks: an increase of ≥1 g/dL or hematocrit increase of ≥3% confirms iron deficiency anemia 1
• If confirmed, continue iron treatment for 2-3 additional months after normalization 1

If no response after 4 weeks despite compliance and absence of acute illness:

• Further evaluate with MCV, RDW, and serum ferritin concentration 1
• In women of African, Mediterranean, or Southeast Asian ancestry, consider thalassemia minor or sickle cell trait 1

Pregnant Women

Primary Prevention:

• Start oral low-dose iron supplementation (30 mg/day) at the first prenatal visit 1
• Encourage iron-rich foods and foods that enhance iron absorption 1

Treatment of Anemia:

• Prescribe 60-120 mg/day of elemental iron for confirmed anemia 1
• If Hb <9.0 g/dL or Hct <27.0%, refer to a physician familiar with anemia during pregnancy for further evaluation 1
• Recheck after 4 weeks: expect Hb increase of 1 g/dL or Hct increase of 3% 1
• When Hb or Hct normalizes for gestational stage, decrease dose to 30 mg/day 1
• If Hb >15.0 g/dL or Hct >45.0% during second or third trimester, evaluate for poor blood volume expansion complications 1

Children (6 months to 19 years)

• Administer 3 mg/kg/day of elemental iron given between meals 2
• Recheck hemoglobin after 4 weeks: expect rise of ≥1 g/dL 2
• If confirmed, reinforce dietary counseling and continue iron treatment for 2 additional months 2
• Recent evidence suggests low-dose iron supplementation (<5 mg/kg/day) combined with treatment durations of either <3 months or >6 months may be optimal for improving Hb levels 3

Men and Postmenopausal Women

• No routine iron supplementation recommended 1
• Iron deficiency or anemia detected during routine examinations should be fully evaluated for underlying cause, as these populations typically do not develop iron deficiency without pathologic blood loss 1

Special Populations

Cancer Patients on Chemotherapy

• Consider erythropoiesis-stimulating agents (ESAs) only when Hb ≤10 g/dL to prevent red blood cell transfusions 1
• ESAs should be used with caution in patients treated with curative intent 1
• Target Hb should not exceed 12 g/dL; dose should be reduced by 25-50% if Hb rises >2 g/dL per 4 weeks 1
• Discontinue ESAs if Hb exceeds 13 g/dL until it falls below 12 g/dL 1
• Evaluate for functional iron deficiency (ferritin >100 ng/mL, TSAT <20%) and consider intravenous iron supplementation 1
• Discontinue ESA therapy if no response (Hb increase <1 g/dL) after 8-9 weeks 1

Chronic Kidney Disease Patients

• Target hemoglobin should NOT exceed 11 g/dL when using ESAs, as higher targets (13-14 g/dL) increase risk of death, myocardial infarction, stroke, and thromboembolism 4
• Intravenous iron is preferred over oral iron for hemodialysis patients, with maintenance dosing of 250-1,000 mg within 12 weeks 1
• Monitor TSAT and ferritin no sooner than 2-7 days after IV iron administration 1

Critically Ill Patients

• Use restrictive transfusion threshold of Hb <70 g/L (7 g/dL) in most critically ill patients, including those with ARDS and septic shock 1
• Available evidence does not support routine use of iron therapy or erythropoietin in critically ill patients 1

Critical Safety Considerations

ESA Use Warnings:

• ESAs increase mortality, myocardial infarction, stroke, and thromboembolism when targeting Hb >11 g/dL in CKD patients 4
• In cancer patients not receiving chemotherapy, ESAs may increase risk of death when targeting Hb 12-14 g/dL 1
• A rate of Hb rise >1 g/dL over 2 weeks may contribute to cardiovascular risks 4

Iron Supplementation Pitfalls:

• Oral iron commonly causes gastrointestinal side effects including constipation (33%), heartburn (14%), and abdominal pain (13%) 5
• Iron deficiency anemia can falsely elevate HbA1c levels in diabetic patients; HbA1c decreases significantly (median 0.4%) following iron treatment 6
• Intravenous iron formulations (ferric carboxymaltose, iron isomaltoside) allow for higher single doses (up to 1000 mg) with shorter infusion times (15 minutes) compared to older formulations 1

Monitoring Response

• Adequate response: Hb increase ≥1 g/dL or Hct increase ≥3% after 4 weeks of oral iron therapy 1, 2
• Non-response: If no improvement after 4 weeks despite compliance, further evaluate with MCV, RDW, and ferritin 1
• For ESA therapy in cancer patients, discontinue if Hb increase <1 g/dL after 8-9 weeks 1