What are the diagnostic criteria for Immune Thrombocytopenic Purpura (ITP)?

From the Guidelines

Immune thrombocytopenia (ITP) is diagnosed through a combination of clinical evaluation, laboratory testing, and exclusion of other causes of thrombocytopenia, with a platelet count less than 100 × 10^9/L and the absence of any obvious initiating and/or underlying cause of the thrombocytopenia, as defined by the international consensus report on the investigation and management of primary immune thrombocytopenia 1. The diagnosis of ITP involves a comprehensive approach, including:

• Clinical evaluation to assess for signs and symptoms of thrombocytopenia, such as mucocutaneous bleeding, and to identify potential underlying causes
• Laboratory testing, including a complete blood count (CBC) to confirm isolated thrombocytopenia, and additional tests such as coagulation studies, liver function tests, and testing for HIV, hepatitis C, and H. pylori to rule out secondary causes of thrombocytopenia
• Exclusion of other causes of thrombocytopenia, including drug-induced thrombocytopenia, hematologic malignancies, and other autoimmune disorders The American Society of Hematology 2019 guidelines for immune thrombocytopenia also emphasize the importance of a thorough diagnostic evaluation, including a physical examination, complete blood count, and peripheral blood smear, as well as testing for underlying conditions that may be contributing to the thrombocytopenia 1. The diagnosis of ITP should be considered in patients with unexplained isolated thrombocytopenia, particularly when there is a history of recent viral illness or in young women, as these are common presentations of ITP 1. In terms of specific diagnostic criteria, the international consensus report on the investigation and management of primary immune thrombocytopenia defines ITP as a platelet count less than 100 × 10^9/L, with the absence of any obvious initiating and/or underlying cause of the thrombocytopenia 1. The American Society of Hematology 2019 guidelines for immune thrombocytopenia also provide guidance on the diagnostic evaluation of ITP, including the use of laboratory tests and physical examination to rule out underlying conditions and confirm the diagnosis of ITP 1. Some key points to consider in the diagnosis of ITP include:
• The importance of excluding other causes of thrombocytopenia, such as drug-induced thrombocytopenia and hematologic malignancies
• The use of laboratory tests, such as coagulation studies and testing for HIV, hepatitis C, and H. pylori, to rule out secondary causes of thrombocytopenia
• The importance of a thorough physical examination to assess for signs and symptoms of thrombocytopenia and to identify potential underlying causes
• The consideration of ITP in patients with unexplained isolated thrombocytopenia, particularly when there is a history of recent viral illness or in young women, as these are common presentations of ITP.

From the Research

Diagnostic Criteria for Immune Thrombocytopenic Purpura (ITP)

The diagnostic criteria for ITP include:

• A platelet count less than 100 × 10^9/L without anemia or leukopenia 2, 3, 4, 5
• Exclusion of secondary causes of thrombocytopenia 2, 3, 4, 5
• A peripheral blood smear showing a small number of large platelets with normal morphology, and no increased number of schistocytes 2
• The diagnosis of ITP is dependent on additional findings, including patient history, physical examination, and blood count 3, 4, 5

Classification of ITP

ITP can be classified into three types, namely:

• Acute
• Subchronic
• Persistent, based on disease duration 3

Treatment Goals

The clinical treatment goals for ITP should be to:

• Resolve bleeding events
• Prevent severe bleeding episodes
• Improve the platelet count to attain a minimum of > 20-30 × 10^9/L 5