From the Guidelines
Leukemia is diagnosed through a combination of blood tests, bone marrow examination, and other specialized tests, with the most critical step being the identification of specific leukemia types and genetic mutations through microscopic examination, flow cytometry, cytogenetic analysis, and molecular testing, as recommended by the most recent guidelines 1. The diagnostic process for leukemia typically begins with a complete blood count (CBC) that may show abnormal white blood cell counts, anemia, or low platelet counts. If leukemia is suspected, a bone marrow aspiration and biopsy are performed to collect marrow samples for further analysis. These samples undergo various tests, including:
- Microscopic examination to identify abnormal cells
- Flow cytometry to determine the type of leukemia cells
- Cytogenetic analysis to detect genetic mutations
- Molecular testing to identify specific genetic abnormalities Additional tests may include:
- Lumbar puncture to check for cancer cells in cerebrospinal fluid
- Imaging studies like CT scans or ultrasounds to assess organ involvement
- Lymph node biopsies if enlarged nodes are present The diagnostic process is typically conducted by hematologists or oncologists who integrate clinical findings with laboratory results to determine the specific type of leukemia, its stage, and appropriate treatment options, as outlined in the guidelines 1. Key diagnostic criteria for chronic lymphocytic leukemia (CLL) include:
- The presence of ≥5000 monoclonal B lymphocytes/µl in the peripheral blood for at least 3 months
- Characteristic small, mature lymphocytes with a narrow border of cytoplasm and a dense nucleus lacking discernible nucleoli
- Co-expression of CD5 and B-cell surface antigens CD19, CD20, and CD23
- Low levels of surface immunoglobulin, CD20, and CD79b compared to normal B cells
- Restriction to expression of either λ or κ immunoglobulin light chains, as specified in the guidelines 1.
From the Research
Diagnosis of Leukemia
To diagnose leukemia, several techniques can be used, including:
- Flow cytometry: a reliable method for diagnosing and classifying leukemia, as seen in a study published in 2024 2
- Morphological examination: using techniques such as Wright-stained smear and cytochemical staining, which can correctly diagnose a large proportion of acute leukemia cases 2
- Special staining techniques: such as myeloperoxidase (MPO) and periodic acid-Schiff (PAS) staining, which can help diagnose acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL) 2
- CD26+ leukemic stem cell assessment: a simple and rapid new diagnostic tool for chronic myeloid leukemia (CML) using flow cytometry 3
- Multiparametric flow cytometry: a highly sensitive method to identify and quantify circulating plasma cells, which can aid in the diagnosis of primary plasma cell leukemia (pPCL) 4
Techniques Used
The following techniques can be used to diagnose leukemia:
- Flow cytometry to evaluate CD26 expression on CD34+/CD38- population for CML diagnosis 3
- Multiparametric flow cytometry to quantify circulating plasma cells for pPCL diagnosis 4
- Morphological examination and cytochemical staining to diagnose AML and ALL 2
Diagnostic Criteria
The diagnostic criteria for leukemia may include: