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Test Code BCLL IGH Somatic Hypermutation Analysis, B-Cell Chronic Lymphocytic Leukemia (B-CLL), Varies

Useful For

Providing prognostic information in patients with newly diagnosed B-cell chronic lymphocytic leukemia

 

This test is not intended for use in providing prognostic information for patient with other B-cell neoplasms or hematopoietic tumors.

Reporting Name

IGH Somatic Hypermutation in B-CLL

Specimen Type

Varies


Shipping Instructions


1. Both refrigerated and ambient specimens must arrive within 7 days of collection.

2. Collect and package specimen as close to shipping time as possible.



Necessary Information


1. Molecular Hematopathology Patient Information: B-Cell Chronic Lymphocytic Leukemia (CLL) for IGVH and/or TP53 Somatic Mutation Testing (T711) is required, see Special Instructions. Testing may proceed without the patient information, however, it aids in providing a more thorough interpretation. Ordering providers are strongly encouraged to fill out the form and send with the specimen.

2. If form is not provided, include the following information with the test request: specimen source, pertinent clinical history (ie, CBC results and relevant clinical notes), and clinical or morphologic suspicion.



Specimen Required


Submit only 1 of the following specimens:

 

Specimen Type: Peripheral blood

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 4 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

3. Label specimen as blood.

Specimen Stability: Refrigerated/ Ambient

 

Specimen Type: Bone marrow

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 2 mL

Collection Instructions:

1. Invert several times to mix bone marrow.

2. Send specimen in original tube.

3. Label specimen as bone marrow.

Specimen Stability: Refrigerated/ Ambient

 

Specimen Type: Extracted DNA from blood or bone marrow

Container/Tube: 1.5- to 2-mL screw-top tube

Specimen Volume: Entire specimen

Collection Instructions:

1. Label specimen as extracted DNA and indicate specimen source (blood or bone marrow).

2. The required volume of DNA is 50 mcL at a concentration of 20 ng/mcL

3. Include volume and concentration on tube.

Specimen Stability: Frozen (preferred)/Refrigerated


Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies 7 days

Reject Due To

Gross hemolysis Reject
Moderately to severely clotted Reject

Clinical Information

During early B-cell development, IGH genes are assembled from multiple polymorphic gene segments that undergo rearrangements and selection, generating variable diversity joining (VDJ) combinations that are unique in both length and sequence for each B cell. In addition, new acquired (somatic) point variations are introduced into the variable (V) regions of mature B cells during the germinal center reaction in lymph nodes, and this process is called somatic hypermutation (SHM). Since chronic lymphocytic leukemia (CLL) originates from the malignant transformation of single lymphoid cells, each daughter cell shares 1 or (sometimes) more unique "clonal" antigen receptor gene rearrangements, which are cell and, therefore, tumor specific (ie, a tumor cell "fingerprint"). Clonal IGHV gene hypermutation status provides important prognostic information for patients with CLL and small lymphocytic lymphoma (SLL). The presence of IGH SHM is defined as greater than 2% difference from the germline VH gene sequence identity (mutated), whereas less than or equal to 2% difference is considered no SHM (unmutated). The status of SHM has clear influence on the median survival of CLL patients. Hypermutation of the IGH variable region is strongly predictive of a good prognosis, while lack of variants predicts a poorer prognosis.

Reference Values

An interpretive report will be provided.

Day(s) Performed

Monday, Wednesday, Friday

Report Available

2 weeks

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81263-IGH (immunoglobulin heavy chain locus) (eg, leukemia and lymphoma, B-cell), variable region somatic mutation analysis

Method Name

Polymerase Chain Reaction (PCR) and Next-Generation Sequencing

Specimen Minimum Volume

Blood: 1 mL
Bone Marrow: 1 mL
Extracted DNA: see Specimen Required

Forms

1. Molecular Hematopathology Patient Information: B-Cell Chronic Lymphocytic Leukemia (CLL) for IGVH and/or TP53 Somatic Mutation Testing (T711) is required, see Special Instructions

2. If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.