Platelet Count

When high

When high (thrombocytosis, >400 x10^9/L):

• Usually reactive: infection, inflammation, iron deficiency, post-exercise
• Persistent elevation >450 without obvious cause warrants haematology review to rule out myeloproliferative disorders
• Iron deficiency (from blood donation) is a common and treatable cause of reactive thrombocytosis
• Investigate inflammation as the driver: CRP, ferritin (acute phase), ESR; AAS-related tissue damage, occult infection, or autoimmune activity can all drive reactive thrombocytosis

Pharmacological options (when platelets remain elevated):

• Low-dose aspirin -- 81mg/day; does not lower platelet count but reduces thrombotic risk; strongly indicated when platelets >450 with concurrent haematocrit >52% or polycythaemia (a very common combo on AAS); cardiology-supervised; monitor for GI bleeding
• Hydroxyurea -- 500-1500mg/day; reserved for confirmed essential thrombocythaemia or JAK2-positive myeloproliferative neoplasm; haematologist-only, not indicated for AAS-reactive thrombocytosis; monitor CBC and for secondary malignancy risk
• Treat the underlying driver first: resolve infection, correct iron deficiency, reduce AAS dose or discontinue offending compound; reactive thrombocytosis almost always resolves once the trigger is addressed without needing platelet-specific pharmacology

When low

When low (thrombocytopenia, <150 x10^9/L):

Possible causes in athletes:

• Chronic NSAID use (ibuprofen, naproxen) can suppress platelets
• Rarely, certain AAS may affect bone marrow production
• Heavy alcohol use, viral infections (EBV, hepatitis), autoimmune conditions

Supplements:

• Vitamin B12 (Methylcobalamin) -- 1000mcg/day (deficiency impairs platelet production)
• Folate (Methylfolate) -- 800mcg/day
• Vitamin C -- 1-2g/day (supports platelet function)
• Papaya Leaf Extract -- 1100mg/day (emerging evidence for raising platelet count)

Lifestyle:

• Discontinue NSAIDs if possible
• Avoid aspirin and fish oil if platelets are very low (<100)
• Investigate cause if persistent -- haematology referral if <100 x10^9/L