Medical Terminology
The medical term for low platelets is thrombocytopenia, defined as a platelet count less than 150,000/μL (or 150 × 10⁹/L) 1, 2.
Clinical Context and Severity Classification
Thrombocytopenia represents a spectrum of severity with distinct clinical implications 1:
- Mild thrombocytopenia (50,000-150,000/μL): Patients are generally asymptomatic with minimal bleeding risk 1
- Moderate thrombocytopenia (20,000-50,000/μL): May present with mild skin manifestations including petechiae, purpura, or ecchymosis 1
- Severe thrombocytopenia (<10,000/μL): Associated with high risk of serious spontaneous bleeding 1
Important Clinical Distinction
A critical pitfall is assuming thrombocytopenia always causes bleeding—certain conditions paradoxically present with both low platelets and thrombosis, including heparin-induced thrombocytopenia, antiphospholipid syndrome, and thrombotic microangiopathies 1, 3. These "thrombosis with thrombocytopenia syndromes" require immediate recognition as they carry high mortality risk if not promptly treated 3.
Verification of True Thrombocytopenia
Before accepting a diagnosis of thrombocytopenia, pseudothrombocytopenia must be excluded by examining a peripheral blood smear or repeating the platelet count in a heparin or sodium citrate tube, as EDTA-dependent platelet clumping can falsely lower automated counts in approximately 0.1% of cases 4, 1.