What are the next steps in managing a patient with thrombocytosis and normal iron saturation?

Management of Thrombocytosis with Normal Iron Saturation

Your patient with elevated platelet count and iron saturation of 22% requires immediate iron supplementation, as this represents iron deficiency that is driving reactive thrombocytosis and significantly increases thromboembolic risk. 1, 2

Iron Status Assessment

Your patient's iron saturation of 22% indicates iron deficiency despite the "normal" range often quoted as 20-50%. 3 This level is insufficient and commonly associated with reactive thrombocytosis. Key points:

• Iron saturation <25% in the setting of thrombocytosis should prompt iron replacement 3
• Check serum ferritin to confirm iron deficiency (target <15 μg/dL confirms deficiency) 3
• Mean corpuscular volume (MCV) <80 fL further supports iron deficiency 3
• Iron deficiency is one of the most common causes of reactive thrombocytosis and can produce extreme elevations (even >1000×10⁹/L) 2, 4

Immediate Management: Iron Supplementation

Start ferrous sulfate 200 mg three times daily immediately to correct the iron deficiency and reverse the thrombocytosis. 3 Alternative formulations include ferrous gluconate or ferrous fumarate if tablets are not tolerated. 3

Critical Monitoring During Iron Replacement

• Monitor hemoglobin closely as iron replacement can cause rapid increases in red cell mass 3
• Continue iron supplementation for three months after correction of anemia to replenish body stores 3
• Adding ascorbic acid enhances iron absorption and should be considered 3
• Platelet count typically normalizes within weeks of adequate iron replacement 2, 4

Thromboembolic Risk Assessment

Iron deficiency-associated thrombocytosis carries significant thromboembolic risk that is often underestimated. 5 Your patient requires:

• Assessment for symptoms of thrombosis (headache, visual changes, chest pain, leg swelling) 6
• Evaluation of cardiovascular risk factors 1
• Consider measuring reticulated platelet percentage if thrombotic symptoms are present (>10% indicates high thrombotic risk) 6

Antiplatelet Therapy Considerations

• If platelet count >1000×10⁹/L with cardiovascular risk factors, consider low-dose aspirin 7
• Aspirin has been shown to reduce reticulated platelet counts and thrombotic events in symptomatic thrombocytosis 6
• However, primary focus should be iron replacement, which addresses the underlying cause 2, 5

Identify the Source of Iron Loss

Investigate the cause of iron deficiency as this will prevent recurrence:

• Menstruating women: Assess for menorrhagia (most common cause in this population) 3
• Gastrointestinal losses: Consider upper endoscopy and colonoscopy if no obvious gynecologic source 3
• Dietary insufficiency: Evaluate nutritional intake 3
• Malabsorption: History of bariatric surgery or celiac disease 2
• Medications: NSAIDs can cause occult GI bleeding 3

Rule Out Primary Thrombocytosis

While iron deficiency is the likely cause, exclude myeloproliferative neoplasms if:

• Thrombocytosis persists after iron repletion 1
• Patient has splenomegaly, constitutional symptoms, or other cytopenias 1
• JAK2, CALR, or MPL mutation testing should be considered if clinical suspicion exists 1

Follow-Up Protocol

• Recheck complete blood count in 2-4 weeks to confirm platelet count is trending down 7
• Monitor hemoglobin and MCV every 3 months for one year after normalization 3
• If platelet count remains elevated after 3 months of adequate iron replacement, refer to hematology 8

Common Pitfalls to Avoid

• Do not perform phlebotomy for thrombocytosis—this will worsen iron deficiency and paradoxically increase thrombotic risk 3, 7
• Do not assume thrombocytosis is benign just because it's reactive—iron deficiency-associated thrombocytosis carries real thromboembolic risk 5
• Do not delay iron supplementation while waiting for additional testing 3
• Do not stop iron too early—continue for 3 months after anemia correction to replenish stores 3