Should an elderly male with macrocytic anemia, thrombocytopenia, and elevated ferritin be referred to hematology?

Hematology Referral for Macrocytic Anemia with Thrombocytopenia

Yes, this patient should be referred to hematology immediately. The combination of macrocytic anemia (MCV 102.5 fL), thrombocytopenia (platelets 130), and normal ferritin with normal B12 represents unexplained cytopenias that require specialist evaluation to exclude serious bone marrow pathology including myelodysplastic syndrome.

Primary Indication for Referral

Patients with unexplained cytopenias should be referred to hematology for evaluation 1. This patient has two concurrent cytopenias (anemia and thrombocytopenia) without an obvious cause, which mandates specialist assessment.

Key Diagnostic Concerns

Macrocytic Anemia Without B12/Folate Deficiency

• The MCV of 102.5 fL indicates macrocytosis, but the B12 level of 460 is normal 1, 2
• When anemia occurs without reduced ferritin (199 ng/mL is normal), evaluation for alternative or complicating etiologies is required 1
• Macrocytosis with normal B12 and folate raises concern for nonmegaloblastic causes including myelodysplastic syndrome, liver disease, hypothyroidism, or primary bone marrow disorders 2

Thrombocytopenia Requiring Investigation

• The platelet count of 130 × 10⁹/L represents mild thrombocytopenia 3
• Thrombocytopenia combined with macrocytic anemia can indicate myelodysplastic syndrome, particularly when megaloblastoid changes are present 4
• The reticulocyte count (absolute 36,920) is inappropriately low for the degree of anemia (Hgb 9.3), suggesting inadequate bone marrow response 1, 5

Iron Studies Interpretation

The iron panel shows:

• Ferritin 199 ng/mL (normal)
• Transferrin saturation 23% (normal, <45%)
• Total iron 49 μg/dL (low-normal)

With transferrin saturation <45%, primary iron overload is effectively ruled out 6. The normal ferritin excludes simple iron deficiency as the cause of anemia 1.

What Hematology Will Evaluate

The hematologist will need to:

• Perform peripheral blood smear examination to assess for dysplastic features, hypersegmented neutrophils, or abnormal cell morphology 1, 3
• Evaluate RDW (15.1% is elevated), which can indicate mixed populations of red cells 1
• Consider bone marrow biopsy if peripheral smear or clinical features suggest myelodysplasia or other primary bone marrow disorder 1, 5
• Rule out hemolysis with haptoglobin, LDH, and indirect bilirubin 1
• Check folate levels (not yet done) and thyroid function 1, 2
• Assess liver function tests, as liver disease causes nonmegaloblastic macrocytic anemia 2

Critical Pitfalls to Avoid

• Do not assume normal B12 excludes all causes of megaloblastic anemia—folate deficiency must still be evaluated 7, 5, 8
• Do not treat empirically with folic acid without excluding B12 deficiency, as folic acid >0.1 mg daily can mask pernicious anemia while neurological damage progresses 7
• Do not dismiss mild thrombocytopenia in the context of macrocytic anemia—this combination warrants bone marrow evaluation 4
• The elevated reticulocyte absolute count (36,920) appears adequate but is actually inappropriately low for a hemoglobin of 9.3, indicating ineffective erythropoiesis 1, 5

Urgency of Referral

This referral should be expedited (within 1-2 weeks) rather than routine because:

• Bicytopenia with macrocytosis raises concern for myelodysplastic syndrome 4
• The patient is elderly, increasing risk of hematologic malignancy 3
• Symptomatic anemia (Hgb 9.3) may require intervention 1