Test ID: LCMS    
Leukemia/Lymphoma Immunophenotyping, Flow Cytometry, Varies

Evaluating lymphocytoses of undetermined etiology

Identifying B- and T-cell lymphoproliferative disorders involving blood and bone marrow

Distinguishing acute lymphoblastic leukemia (ALL) from acute myeloid leukemia (AML)

Immunologic subtyping of ALL

Distinguishing reactive lymphocytes and lymphoid hyperplasia from malignant lymphoma

Distinguishing between malignant lymphoma and acute leukemia

Phenotypic subclassification of B- and T-cell chronic lymphoproliferative disorders, including chronic lymphocytic leukemia, mantle cell lymphoma, and hairy cell leukemia

Recognizing AML with minimal morphologic or cytochemical evidence of differentiation

Recognizing monoclonal plasma cells

The testing process begins with a screening panel. The screening panel will be charged based on the number of markers tested (FIRST for first marker, ADD1 for each additional marker). The interpretation will be based on markers tested in increments of 2 to 8, 9 to 15, or 16 and greater. In addition, reflex testing may occur to fully characterize a disease state or clarify any abnormalities from the screening test. Reflex tests will be performed at an additional charge for each marker tested (FIRST if applicable, ADD1 if applicable).

In addition to reflexing flow cytometric panels, AML FISH testing for PML-RARA translocation t(15;17) may be added by the Mayo Clinic pathologist to exclude acute promyelocytic leukemia if there is morphologic suspicion or if blasts and promyelocytes are CD34-negative and HLA-DR-negative.

The triage panel is initially performed to evaluate for monotypic B cells by kappa and lambda light chain expression, increased numbers of blast cells by CD34 and CD45 expression along with side scatter gating, and increased plasma cells by CD45 expression and side scatter gating. The triage panel also includes antibodies to assess the number of CD3-positive T cells and CD16-positive/CD3-negative natural killer (NK) cells present. This triage panel also determines if there is an increase in the number of T cells that aberrantly coexpress CD16, an immunophenotypic feature of T-cell granular lymphocytic leukemia.

This panel, together with the provided clinical history and morphologic review, is used to determine what, if any, additional testing is needed for disease diagnosis or classification. If additional testing is required, it will be added per the algorithm to fully characterize a disease state with a charge per unique antibody tested.

If no abnormalities are detected by the initial panel, no further flow cytometric assessment will be performed unless otherwise indicated by specific features of the clinical presentation or prior laboratory results.

Additional FISH or molecular testing may be recommended by the Mayo pathologist to facilitate diagnosis. The referring physician or pathologist will be contacted to confirm the addition of any of these tests. Cytogenetic FISH Studies:

-CCND1/IGH translocation t(11;14), to exclude mantle cell lymphoma in cases of CD5+CD23- B-cell lymphoproliferative disorder.

-TCL-1 break-apart at 14q32, to exclude T-cell prolymphocytic leukemia in cases with CD4-positive T-cell lymphoproliferative disorder (phenotypic aberrancy or very tight CD4+ population with high CD4:CD8 ratio).

-MYC break-apart at 8q24, with or without IGH-BCL2 t(14;18) and BCL6 break-apart at 3q27, for suspected high grade B-cell lymphomas, based on morphologic assessment and immunophenotype (usually CD10-positive).

Molecular Genetic Studies:

-T-cell receptor gene rearrangement to examine clonality of T cells in cases showing phenotypically aberrant T-cell population.

Cytochemical Stains:

-Confirmatory cytochemical stains as needed.

The following algorithms are available in Special Instructions:

-Bone Marrow Staging for Known or Suspected Malignant Lymphoma Algorithm

-Acute Myeloid Leukemia: Testing Algorithm

-Acute Myeloid Leukemia: Relapsed with Previous Remission Testing Algorithm

-Acute Promyelocytic Leukemia: Guideline to Diagnosis and Follow-up

• Hematopathology Patient Information
• Bone Marrow Staging for Known or Suspected Malignant Lymphoma Algorithm
• Acute Promyelocytic Leukemia: Guideline to Diagnosis and Follow-up
• Acute Myeloid Leukemia: Testing Algorithm
• Acute Myeloid Leukemia: Relapsed with Previous Remission Testing Algorithm

Immunophenotyping