Initial Workup for Acute Leukemia
The initial workup for acute leukemia requires bone marrow aspirate and biopsy with comprehensive ancillary testing including flow cytometry, conventional karyotyping, FISH, and molecular genetic studies, alongside specific laboratory panels to assess for tumor lysis syndrome and coagulopathy. 1
Clinical History and Physical Examination
Obtain specific clinical data including:
- Age, sex, and ethnicity (Hispanics have worse outcomes in ALL and higher incidence of BCR-ABL1-like ALL) 1
- Prior hematologic disorders, predisposing syndromes, or malignancies
- Exposure history: cytotoxic therapy, radiation, benzene, formaldehyde, butadiene
- Family history of hematologic disorders or malignancies
- Recent confounding factors: growth factors, transfusions, medications 1
Physical examination must document:
- Neurologic findings
- Tumor masses (especially mediastinal)
- Organomegaly (liver, spleen)
- Cutaneous or nodal involvement 1
Laboratory Testing
Initial Blood Work (All Patients)
Routine hematology:
- CBC with differential
- Peripheral blood smear review (mandatory) 1
Metabolic panel to assess tumor lysis syndrome:
- Comprehensive metabolic panel
- Lactate dehydrogenase (LDH)
- Phosphate and uric acid levels
- Monitor at diagnosis and throughout induction 1
Coagulation panel (critical for acute promyelocytic leukemia):
- Prothrombin time (PT)
- Partial thromboplastin time (PTT)
- Fibrinogen activity 1
Bone Marrow Evaluation
Sample Collection
Obtain fresh bone marrow aspirate for:
- Morphologic smears
- Flow cytometry immunophenotyping
- Conventional cytogenetics (karyotype)
- FISH studies
- Molecular genetic testing 1
Also obtain:
- Bone marrow core biopsy with touch preparations
- Marrow clots if available 1
Critical caveat: If bone marrow aspirate is unobtainable (dry tap) or patient is clinically unstable, peripheral blood can substitute if sufficient blasts are present. Touch imprint preparations from core biopsy should be evaluated, and an additional unfixed core in tissue culture medium can be submitted for disaggregation for flow and genetic studies 1.
Ancillary Testing (Mandatory)
Flow Cytometry Immunophenotyping
Perform comprehensive multicolor flow cytometry panel sufficient to distinguish:
- AML (including acute promyelocytic leukemia)
- B-ALL
- T-ALL
- Mixed phenotype acute leukemia (MPAL) 1
If flow cytometry on bone marrow is diagnostic, additional flow on peripheral blood is unnecessary 1.
Cytogenetic Analysis
Conventional karyotyping (mandatory):
- Must be performed on bone marrow
- Cannot be replaced by FISH or molecular testing 1
FISH testing based on subtype:
- Adult ALL: t(9;22)/BCR-ABL1, KMT2A (MLL) translocations 1
- Childhood ALL: ETV6-RUNX1, iAMP21, trisomy 4 and 10, BCR-ABL1 1
- MPAL: t(9;22)/BCR-ABL1, KMT2A translocations (mandatory) 1
Molecular Genetic Testing
Perform targeted molecular studies based on leukemia subtype:
- RT-PCR for fusion transcripts
- NGS mutation profiling when indicated
- Specific gene panels (e.g., FLT3, NPM1, CEBPA for AML) 1
The 2022 ELN recommendations emphasize molecular characterization for risk stratification and targeted therapy selection 2.
Imaging Studies
Obtain imaging to evaluate:
- Mediastinal masses
- Hepatosplenomegaly
- Nodal involvement
- Extramedullary disease 1
CNS Evaluation
For ALL Patients (Mandatory)
Lumbar puncture with CSF analysis:
- Cell count
- Cytocentrifuge preparation with blast enumeration
- Flow cytometry (recommended)
- Pathologist review required 1
For Non-ALL Patients
CSF evaluation may be performed under certain circumstances when no clinical contraindication exists 1.
Important Pitfalls to Avoid
Do not defer bone marrow biopsy if referring to another institution - this causes duplicate procedures, patient discomfort, and delays. The treatment center should perform the initial invasive procedures 1.
Do not rely solely on FISH or molecular testing - conventional karyotyping remains mandatory as it can detect unexpected abnormalities 1.
Do not perform redundant flow cytometry - if peripheral blood flow is diagnostic with sufficient blasts, bone marrow flow adds no value 1.
Ensure all testing is performed in accredited laboratories compliant with regulatory requirements 1.
Specimen Handling
Cryopreserve cells or nucleic acids for future molecular studies. Store formalin-fixed, non-decalcified paraffin-embedded tissue and unstained smears under appropriate conditions 1.
Reporting Requirements
The pathologist must issue an initial report including laboratory, morphologic, immunophenotypic, and cytochemical data, with a list of pending tests. Addenda must be issued as additional results become available. Use current WHO terminology for final diagnosis and classification 1.