Diagnostics

• Initial evaluation

  • Suspect acute leukemia in patients with suggestive clinical or laboratory features.

  • Confirm the diagnosis with a morphological assessment.

• Further diagnostic studies: Immunophenotype, cytogenetics, and molecular genetic testing should be obtained in order to identify the subtype of acute leukemia.

In order to choose the best treatment strategy, the morphological assessment, immunophenotype, and genetic studies should be as comprehensive as possible.

• Complete blood count and peripheral blood smear

  • Leukocytes: The white blood cell count (WBC) may be elevated, normal, or low and is not a reliable diagnostic marker.

  • Platelets: typically mild to severe thrombocytopenia

  • Hemoglobin: typically anemia

  • Peripheral blood smear: presence of blasts (immature WBCs)

• Liver chemistries and renal function tests: may be abnormal (e.g., secondary to disease infiltration)

• Comprehensive metabolic panel and other metabolic studies

  • Often abnormal due to increased cell lysis (see also “Tumor lysis syndrome”)

  • Common findings include derangements of:

    • Sodium: hyponatremia OR hypernatremia

    • Potassium: hypokalemia OR hyperkalemia

    • Calcium: hypocalcemia OR hypercalcemia

    • Phosphate: hypophosphatemia OR hyperphosphatemia

    • ↑ LDH

    • ↑ Uric acid

• Coagulation studies: Mild coagulopathy may be present. Studies may also help to identify features of DIC.

The identification of DIC suggests APL, which is a medical emergency. Consult hematology and/or oncology immediately and transfer the patient to a critical care unit.

Histopathological features should be assessed using bone marrow aspiration and biopsy. If unavailable, a peripheral blood smear may be sufficient.

These studies are used to further characterize the cell line involved; some characteristics may be associated with a better response to certain therapies. These studies should be ordered in consultation with a specialist.

Consider the following studies to detect extramedullary disease based on the subtype of acute leukemia and clinical evaluation of the patient:

• CNS infiltration (common in ALL)

  • Perform a lumbar puncture and obtain CSF flow cytometry.

  • Consider brain and spine CT or MRI.

• Testicular infiltration (relatively common in ALL): testicular ultrasound

• Thymic infiltration (primarily in T-cell ALL): Chest x-ray or CT chest may show a mediastinal mass.

• Hepatosplenic infiltration: Abdominal CT or ultrasound may show organ enlargement.

• Other forms of extramedullary disease: Consider PET-CT and/or lymph node biopsy.