Diagnostic Criteria for Acute Myeloid Leukemia (AML) in Adults

Core Diagnostic Requirements

The diagnosis of AML in adults requires examination of peripheral blood and bone marrow samples with a minimum of 20% blasts in either specimen, along with comprehensive workup including morphological examination, cytochemistry, immunophenotyping, cytogenetics, and molecular genetics, as recommended by the American Society of Clinical Oncology 1, 2
Bone marrow aspirate and/or peripheral blood examination is essential, with evaluation of at least 500 nucleated cells, according to the American Society of Hematology 1
Presence of ≥20% myeloblasts in bone marrow or peripheral blood is required for most AML diagnoses, as stated by the National Comprehensive Cancer Network 2, 1
In AML with monocytic differentiation, monoblasts and promonocytes (but not abnormal monocytes) are counted as blast equivalents, as defined by the World Health Organization 3

Morphological examination, including evaluation of peripheral blood smear and bone marrow aspirate smears, is a crucial diagnostic tool, as recommended by the American Society of Clinical Oncology 1, 4
Cytochemistry, such as nonspecific esterase (NSE) stains, shows diffuse cytoplasmic activity in approximately 80% of monoblasts, according to the College of American Pathologists 3
Immunophenotyping by flow cytometry with a panel sufficient to distinguish AML from other acute leukemias is essential, as stated by the American Society of Hematology 1, 4
Cytogenetic analysis, including conventional karyotyping and FISH, is mandatory for proper classification, as recommended by the National Comprehensive Cancer Network 1, 3, 4
Molecular genetic testing, including FLT3-ITD testing, NPM1, CEBPA, and RUNX1 mutation analysis, is crucial for diagnosis and risk assessment, as stated by the American Society of Clinical Oncology 1, 3

Patient's age (>60 years associated with adverse prognosis) is a significant risk factor, as reported by the American Society of Clinical Oncology 1, 4
Initial leukocyte count is an important prognostic factor, as stated by the National Comprehensive Cancer Network 4, 1
AML subtype and karyotype data, including favorable and adverse cytogenetic abnormalities, are essential for risk assessment, as recommended by the American Society of Hematology 4, 1
Molecular markers, such as mutations in C/EBPα gene and nucleophosmin gene, and FLT3 gene alterations, are significant prognostic factors, as reported by the College of American Pathologists 4

Coagulation screening should be performed, particularly if morphology suggests acute promyelocytic leukemia, as recommended by the American Society of Clinical Oncology 4
HLA typing of patients and family members should be conducted for potential allogeneic stem cell transplantation candidates, as stated by the National Comprehensive Cancer Network 4
If extramedullary disease is suspected, appropriate imaging (PET/CT) should be performed, as recommended by the American Society of Hematology 1
For CNS signs or symptoms, evaluate using appropriate imaging (CT or MRI), as stated by the American Academy of Neurology 1

Starting chemotherapy before obtaining satisfactory material for all diagnostic tests is a common pitfall, as warned by the American Society of Clinical Oncology 1
Relying solely on molecular genetic or FISH testing without conventional cytogenetic analysis is inappropriate, as stated by the College of American Pathologists 1
Failing to recognize hyperleukocytosis (WBC >100,000/μL) as a medical emergency requiring immediate intervention is a critical mistake, as reported by the American Society of Hematology 5

Patients with hyperleukocytosis require emergency measures, including apheresis or hydroxyurea, as recommended by the American Society of Clinical Oncology 3, 5
Prompt institution of definitive therapy is essential for patients with high WBC counts, as stated by the National Comprehensive Cancer Network 3
Excessive red blood cell transfusions in patients with hyperleukocytosis can worsen symptoms by increasing blood viscosity, as warned by the American Association of Blood Banks 5