From the Guidelines
Aplastic anemia is diagnosed when at least two of the following three peripheral blood findings are present: hemoglobin less than 10 g/dL, platelet count less than 50,000/μL, and neutrophil count less than 1,500/μL, along with bone marrow examination showing hypocellularity (less than 25-30% of normal cellularity) with replacement of hematopoietic cells by fat. The diagnostic criteria for aplastic anemia, also known as bone marrow failure, involve a combination of peripheral blood and bone marrow findings. According to the study by Bennett and Orazi 1, the French-American-British Cooperative Leukemia Working Group proposed criteria to distinguish hypocellular acute myeloid leukemia from hypocellular myelodysplastic syndromes and aplastic anemia.
Key Diagnostic Criteria
- Hemoglobin less than 10 g/dL
- Platelet count less than 50,000/μL
- Neutrophil count less than 1,500/μL
- Bone marrow examination showing hypocellularity (less than 25-30% of normal cellularity) with replacement of hematopoietic cells by fat
The severity of aplastic anemia is further classified as non-severe, severe, or very severe based on specific blood count thresholds. Severe aplastic anemia is defined by neutrophils less than 500/μL, platelets less than 20,000/μL, and reticulocytes less than 1% 1. Very severe aplastic anemia has the same criteria but with neutrophils below 200/μL. This classification is important for treatment decisions, as severe and very severe cases typically require immediate intervention with either immunosuppressive therapy or hematopoietic stem cell transplantation, while non-severe cases may be observed or treated with less aggressive approaches depending on transfusion requirements and quality of life.
Importance of Accurate Diagnosis
Accurate diagnosis of aplastic anemia is crucial for determining the appropriate treatment approach and improving patient outcomes. The study by Bennett and Orazi 1 provides a standardized approach for diagnosing aplastic anemia, which is essential for clinicians to make informed treatment decisions. In contrast, the study by the ESMO clinical practice guidelines for diagnosis, treatment, and follow-up of acute myeloblastic leukaemias in adult patients 1 focuses on the diagnostic work-up for AML, which is not directly relevant to the diagnosis of aplastic anemia. Therefore, the diagnostic criteria proposed by Bennett and Orazi 1 should be prioritized for diagnosing aplastic anemia.
From the Research
Diagnostic Criteria for Aplastic Anemia
The diagnostic criteria for aplastic anemia (bone marrow failure) include:
- Peripheral blood pancytopenia and hypocellular bone marrow 2
- Bone marrow cellularity and blood cell count criteria, such as:
- ANC < 500/microl
- Platelet < 20,000/microl
- Reticulocyte < 20,000/microl 3
- Red blood cell distribution width and absolute lymphocyte and reticulocyte counts can also be used to diagnose aplastic anemia 4
Diagnosis and Treatment
Diagnosis of aplastic anemia requires a comprehensive approach with prompt evaluation for inherited and secondary causes of bone marrow aplasia, while providing aggressive supportive care 5. The choice of frontline therapy is determined by a number of factors including AA severity, age of the patient, donor availability, and access to optimal therapies 5.
Severity Classification
Aplastic anemia can be classified as severe or non-severe, with severe aplastic anemia defined as meeting at least two of the following criteria:
- ANC < 500/microl
- Platelet < 20,000/microl
- Reticulocyte < 20,000/microl 3 Non-severe aplastic anemia is defined as hypocellular marrow with cytopenia in the peripheral blood, which does not meet the criteria for severe aplastic anemia 3
Diagnostic Tools
Diagnostic tools for aplastic anemia include: