Acute Leukemia Profile

Test Includes:

Initial profile of B-cell, T-cell, and myeloid markers (CD2, CD3, CD7, CD10, CD13, CD14, CD19, CD20, CD33, CD34, CD45, CD71, CD117, HLA-DR); supplemental markers added as needed (CD1a, CD4, CD5, CD8, CD61, glycophorin A, TdT).

Special Instructions:

Pathologist consultation is available Monday through Friday.

Specimen:

Whole blood or bone marrow aspirate.

Volume:

Two 7-mL EDTA whole blood tubes or one 7-mL EDTA whole blood tube and 2 cc EDTA or heparinized bone marrow aspirate. One EDTA whole blood tube is for an optional CBC.

Container:

Lavender-stopper (EDTA whole blood or bone marrow) tube or green-stopper (heparinized bone marrow aspirate) tube.

Collection:

Submit at room temperature using Leukemia/Lymphoma Specimen Transport Kit. Draw specimen so it will arrive in the laboratory Monday through Saturday and within 24 hours of collection. Specimens cannot be held over the weekend. Please state date and time of collection and the name and telephone/fax number of the physician to whom results are to be called/transmitted on the test request form.

Storage:

Maintain specimen at room temperature.

Causes for Rejection:

Specimen frozen; specimen in formalin or other fixative; clotted specimen; hemolysis; blood more than 72 hours old; bone marrow aspirates older than 5 days.

Use:

Lineage assignment in acute leukemia is necessary for selecting appropriate therapy and is useful in assessing prognosis. Multiparameter analysis using three- and four-color immunophenotyping techniques is a rapid and specific method of assigning lineage in acute leukemia. This profile is also useful in distinguishing lymphoid from myeloid blast crisis in CML and immunophenotyping lymphoblastic lymphoma in blood or bone marrow.

Limitations:

This immunophenotyping profile should not be used as a diagnostic test for leukemia. In most cases, this profile is not useful in monitoring residual disease after treatment. Tdt is available only as a supplemental marker to distinguish null-cell ALL from acute undifferentiated leukemia and to characterize cases of apparent mixed lineage leukemia further. When the morphology and immunophenotype suggest a diagnosis of acute promyelocytic leukemia (APL), confirmation by testing for the retinoic acid receptor gene rearrangement by cytogenetic or molecular methods is recommended.

Methodology:

Immunophenotyping by flow cytometry.

Additional Information:

Immunophenotyping and cytogenetic analysis are increasingly being used to supplement the traditional methods (morphology and cytochemistry) of classifying acute leukemias and to provide prognostic information. Acute lymphoblastic leukemia (ALL) can be classified into undifferentiated null T- and B-cell lineages. In ALL of B-cell lineage, expression of CD10 (CALLA) is a favorable prognostic factor. Acute myelogenous leukemias (AML) are a heterogeneous group. In cases where morphology and cytochemical staining is equivocal, immunophenotyping can be useful. Immunophenotyping is particularly useful in classifying megakaryoblastic leukemia (FABM7). A combination of characteristic light scattering properties and myeloid phenotype can suggest a diagnosis of acute promyelocytic leukemia (FABM3). Confirmation of the retinoic acid receptor gene rearrangement by cytogenetic or molecular methods is recommended.