What is the initial workup and treatment for a patient with anemia?

Anemia Workup and Treatment

The initial workup for anemia should include a complete blood count with red cell indices, peripheral blood smear, reticulocyte count, iron studies (serum ferritin and transferrin saturation), vitamin B12 and folate levels, and liver function tests to identify the underlying cause before initiating appropriate treatment. 1

Diagnostic Approach

Initial Laboratory Evaluation

• Complete Blood Count (CBC) with red cell indices (MCV, MCH, MCHC)
• Peripheral Blood Smear to examine red cell morphology
• Reticulocyte Count to assess bone marrow response
• Iron Studies:
  • Serum Ferritin (iron stores)
  • Transferrin Saturation (TSAT) (iron availability)
• Vitamin B12 and Folate Levels
• Liver Function Tests
• C-reactive Protein (CRP) to evaluate inflammation

Additional Testing Based on Initial Results

For Microcytic Anemia (Low MCV):

• If ferritin < 30 μg/L: confirms iron deficiency 1
• If normal/high ferritin with low TSAT: consider anemia of inflammation 2
• Consider hemoglobin electrophoresis to rule out thalassemia 1

For Macrocytic Anemia (High MCV):

• Vitamin B12 and folate levels
• Thyroid function tests
• Consider alcohol use, liver disease, medications 1

For Normocytic Anemia:

• Evaluate for chronic disease, kidney disease, or hemolysis
• If GFR < 30 ml/min per 1.73 m², monitor hemoglobin at least every three months 3

Treatment Algorithm

Iron Deficiency Anemia

1. Oral Iron Therapy:

   • First-line treatment: 100-200 mg elemental iron daily 1
   • Continue for at least 3 months after hemoglobin normalization to replenish stores
   • Monitor response with repeat CBC in 4-8 weeks

2. Intravenous Iron:

   • Consider if oral iron is not tolerated or ineffective
   • Indicated for patients with functional iron deficiency (TSAT < 20% and ferritin > 100 ng/mL) 3
   • Typical dose: 1000 mg given as single or multiple doses 3

Vitamin B12 Deficiency

1. For Pernicious Anemia:

   • Intramuscular cyanocobalamin 100 mcg daily for 6-7 days
   • Then every other day for 7 doses
   • Then every 3-4 days for 2-3 weeks
   • Maintenance: 100 mcg monthly for life 4
   • Avoid intravenous route as most vitamin will be lost in urine 4

2. For B12 Deficiency with Normal Absorption:

   • Initial treatment similar to pernicious anemia based on severity
   • Transition to oral B12 for chronic treatment 4

Anemia of Chronic Disease/Inflammation

• Treat underlying condition
• For patients with chronic kidney disease (GFR < 30 ml/min):
  • Complete workup if hemoglobin < 12 g/dL (women) or < 13 g/dL (men) 3
  • Treat iron deficiency if identified 3
  • Consider erythropoietin or analogue if anemia persists despite iron therapy 3
  • Monitor BP with each erythropoietin dose 3

Transfusion Therapy

• Consider in patients with hemoglobin < 7-8 g/dL or severe symptoms 3
• Immediate intervention for symptomatic anemia requiring rapid correction

Special Considerations

Chronic Kidney Disease

• If GFR < 30 ml/min per 1.73 m², check hemoglobin at least every three months 3
• Monitor BP closely if patient receives erythropoietin 3

Cancer-Related Anemia

• ESA therapy recommended for symptomatic anemia in patients receiving chemotherapy with Hb < 10 g/dL 3
• Target hemoglobin level: stable 12 g/dL 3
• Not recommended for patients not on chemotherapy 3

Gastrointestinal Evaluation

• Men and post-menopausal women with unexplained iron deficiency anemia should undergo GI evaluation (upper endoscopy and colonoscopy) 1

Common Pitfalls to Avoid

1. Incomplete Workup: Failing to identify underlying cause before treatment
2. Misinterpreting Ferritin: In inflammatory states, ferritin may be falsely elevated despite iron deficiency
3. Overlooking Combined Deficiencies: Iron deficiency can coexist with B12/folate deficiency
4. Inadequate Treatment Duration: Iron therapy should continue for 3 months after hemoglobin normalization
5. Inappropriate ESA Use: ESAs should only be used in specific circumstances, particularly for patients on chemotherapy or with chronic kidney disease

By following this systematic approach to anemia evaluation and treatment, clinicians can effectively identify and manage the underlying causes, leading to improved patient outcomes and quality of life.