When to refer to hematology for iron deficiency anemia with thrombocytosis (elevated platelet count)?

From the Guidelines

Referral to hematology for iron deficiency anemia with a platelet count of 445 is not immediately necessary, and primary care physicians should first treat the underlying iron deficiency with oral iron supplementation. The provided evidence from the 2021 study in the journal Blood 1 emphasizes the importance of treating iron deficiency anemia, particularly in patients with hereditary hemorrhagic telangiectasia (HHT), but does not specifically address the platelet count threshold for hematology referral. Key points to consider in managing iron deficiency anemia include:

• Initial therapy with oral iron, with a dose of 35-65 mg of elemental iron daily, as recommended by the expert panel 1
• Assessment of adequacy of response to iron replacement at 1 month, with a goal of achieving a hemoglobin rise of ≥1.0 g/dL and normalization of ferritin and transferrin saturation 1
• Consideration of intravenous iron replacement for patients who do not respond to oral iron or have severe anemia 1
• Evaluation for additional causes of anemia if there is an inadequate response to iron replacement 1 Hematology referral may be warranted if there is no improvement after adequate iron replacement therapy, if there are concerning features like significant bleeding, very severe anemia, other unexplained cytopenias, or if the cause of iron deficiency remains unclear despite appropriate workup. In the context of a platelet count of 445, which is only mildly elevated, reactive thrombocytosis is a common occurrence with iron deficiency anemia, and the primary focus should be on treating the underlying iron deficiency. The expert panel recommends considering evaluation for additional causes of anemia in the setting of an inadequate response to iron replacement 1, which supports a stepped approach to management, starting with primary care and reserving hematology referral for more complex or refractory cases.

From the Research

Referral to Hematology for Iron Deficiency Anemia

• Iron deficiency anemia (IDA) with a platelet count of 445 is considered thrombocytosis, which is a common clinical hematological condition in patients with IDA 2.
• The study found that patients with IDA and thrombocytosis had more severe anemia, lower ferritin, and more advanced iron deficiency than those without thrombocytosis 2.
• Iron supplementation has been shown to decrease platelet count in patients with IDA-induced thrombocytosis, with half of the patients resolving thrombocytosis after 2 weeks of treatment and all patients resolving thrombocytosis after 6 weeks 2.

Management of Iron Deficiency Anemia

• The management of IDA involves three steps: identification of ID/IDA, investigation of and management of the underlying etiology of ID, and iron repletion 3.
• Iron repletion options include oral and intravenous (IV) iron formulations, with IV iron being more effective in certain populations 3, 4.
• Judicious use of red cell blood transfusion is recommended and should be considered only for severe, symptomatic IDA with hemodynamic instability 3.

Referral Criteria

• Patients with IDA and thrombocytosis should be referred to hematology for further evaluation and management, especially if they have a high risk of thrombosis or if their platelet count does not decrease with iron supplementation 2.
• Referral to hematology may also be considered for patients with severe or symptomatic IDA, or for those who do not respond to initial treatment 3, 4.

Note: The study with reference_id 5 is not relevant to the question and is not cited. Similarly, the study with reference_id 6 provides information on guidelines for the diagnosis and treatment of iron deficiency anemia but does not directly address the question of when to refer to hematology.