What is the best course of action for a patient with a history of anemia, currently presenting with mild anemia, an increased RDW, and a recent decrease in platelet count?

Management of Anemia with Elevated RDW and Thrombocytosis

This patient requires immediate comprehensive workup to identify the underlying cause of anemia before initiating treatment, with particular attention to iron deficiency, vitamin B12/folate deficiency, and occult gastrointestinal blood loss given the elevated RDW and recent platelet decline. 1

Initial Diagnostic Evaluation

The elevated RDW (18.7) is a critical finding that indicates significant red cell heterogeneity and suggests an evolving or mixed anemia process. 2 You must obtain:

• Complete iron studies: serum ferritin, transferrin saturation (TSAT), and total iron binding capacity 1
• Vitamin B12 and folate levels: essential given the elevated RDW which can occur in megaloblastic anemia 1, 3
• Peripheral blood smear review: mandatory to assess red cell morphology and identify specific patterns 1
• Reticulocyte count: to determine if bone marrow is responding appropriately 1
• Comprehensive metabolic panel: including renal function to assess for chronic kidney disease 1
• Occult blood testing and consideration of GI evaluation: particularly important given the anemia history 1

Interpretation of Current Laboratory Values

The hemoglobin improvement from 9.5 to 10.4 g/dL suggests either spontaneous recovery or response to an unidentified intervention, but this remains mild anemia by standard definitions (Hb <12 g/dL for women, <13 g/dL for men). 1, 4

The RDW elevation from 18.1 to 18.7 is concerning because:

• RDW >17.1 strongly suggests iron deficiency anemia 2
• However, elevated RDW can also occur in B12 deficiency, though 31% of pernicious anemia patients have normal RDW 3
• The rising RDW indicates worsening anisocytosis and suggests the anemia is not resolving 2

The platelet decline from 875 to 525 (×10⁹/L) is significant:

• The initial thrombocytosis (>400 ×10⁹/L) can occur with iron deficiency 1
• The dramatic drop suggests either resolution of reactive thrombocytosis or a separate evolving process requiring monitoring 1

Treatment Algorithm Based on Workup Results

If Iron Deficiency is Confirmed (Ferritin <100 ng/mL and TSAT <30%):

• Initiate oral iron supplementation (or IV iron if malabsorption suspected) for 1-3 months 1
• Investigate source of blood loss: GI evaluation is mandatory in adults without obvious cause, as occult malignancy must be excluded 1
• Serum ferritin <12 μg/dL is diagnostic of iron deficiency; ferritin 12-100 μg/dL with TSAT <30% also indicates deficiency 1

If B12/Folate Deficiency is Identified:

• Begin appropriate vitamin supplementation immediately 1
• Folate: 5 mg daily for 2 weeks, then 5 mg weekly for 6 weeks 1
• B12: per standard replacement protocols based on severity

If Anemia of Chronic Disease is Suspected:

• Address underlying inflammatory or malignant condition 1
• Consider erythropoiesis-stimulating agents only if hemoglobin approaches or falls below 10 g/dL in specific contexts (e.g., chemotherapy-induced anemia, chronic kidney disease) 1

Transfusion Considerations

Blood transfusion is NOT indicated at this hemoglobin level (10.4 g/dL) unless the patient is severely symptomatic. 5, 6

• Transfusion threshold is <7 g/dL for stable patients without cardiac disease 5, 6
• Higher thresholds (7-8 g/dL) apply only to patients with acute coronary syndrome or significant cardiac comorbidities 6
• At Hb 10.4 g/dL, focus on identifying and treating the underlying cause rather than transfusing 1

Critical Pitfalls to Avoid

• Do not assume dietary insufficiency alone explains the anemia without complete GI evaluation in adults, as malignancy may present with mild anemia 1
• Do not treat empirically without establishing the diagnosis, as this may mask serious underlying pathology 1
• Do not ignore the platelet trend: continue monitoring as the decline from 875 to 525 requires explanation 1
• Do not use erythropoiesis-stimulating agents without proper indication, as they carry thrombotic risks and are not indicated for mild anemia without specific contexts 1

Monitoring Plan

• Recheck complete blood count in 4-6 weeks after initiating treatment 1
• Monitor platelet count to ensure continued normalization 1
• Reassess RDW as it should decrease with effective treatment of iron or vitamin deficiency 2
• If no improvement or worsening occurs, consider bone marrow examination 1