American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the nature of the diagnosis for TTP?

1. Requires only laboratory confirmation

2. Requires clinical diagnosis based on symptoms

3. Is primarily a surgical condition

4. Is based on imaging studies

The correct answer is: Requires clinical diagnosis based on symptoms

The diagnosis of Thrombotic Thrombocytopenic Purpura (TTP) is fundamentally based on clinical evaluation, particularly the presence of characteristic symptoms such as a pentad of findings: microangiopathic hemolytic anemia, thrombocytopenic purpura (which may present as petechiae or ecchymosis), neurological symptoms, renal dysfunction, and fever. While laboratory tests, including a complete blood count (CBC), peripheral blood smear, and assays for ADAMTS13 enzyme activity can support the diagnosis, the clinical context and the constellation of symptoms are crucial in making the diagnosis of TTP. In this case, a clinical diagnosis is essential because the symptoms guide the clinician in considering TTP among other differential diagnoses. Laboratory confirmation can assist in supporting the diagnosis but cannot replace the need for a detailed clinical assessment of the patient’s symptoms and overall condition.