Thrombocytopenia and platelet dysfunction

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Definition of thrombocytopenia

Platelet count less than 150 × 10⁹/L or less than the lower limit of normal as defined by a local laboratory.

Evaluation

May consist of:

• CBC with differential
• Comprehensive metabolic panel, including liver function tests (LFTs)
• Vitamin B12
• Folate
• Assessment for liver disease, hepatomegaly, fatty liver, splenomegaly
• Peripheral smear, platelet clumps
• Clinical history (bleeding, temporality, recent infections), TTP/aHUS
• Thrombotic history (e.g., heparin/HIT)
• Lifestyle factors (e.g. alcohol)
• Medications
• Hepatitis serologies
• HIV
• ANA, lupus
• Pseudothrombocytopenia, EDTA-induced clumping (draw sample in blue top citrate tube)
• Pregnancy/gestational thrombocytopenia
• ITP

Relevant diagnoses

• Atypical hemolytic uremic syndrome
• Glanzmann thrombasthenia
• Immune thrombocytopenia (ITP)
• Heparin-induced thrombocytopenia (HIT)
• Thrombocytopenia in liver disease
• Acquired thrombotic thrombocytopenic purpura