Test Catalog

Test Id : BCLL

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

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Overview

Test Catalog

Useful For
Suggests clinical disorders or settings where the test may be helpful

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.

Highlights

Although the determination of variant status can be accomplished by polymerase chain reaction followed by Sanger sequencing, that approach only allows for analysis of single samples at a time. Next-generation sequencing technology represents a significant improvement over existing Sanger assays by allowing for batch sample analysis and simultaneous identification of clonal IGH rearrangement, the tumor-specific rearrangement sequence, and determination of somatic variant percent.

Method Name
A short description of the method used to perform the test

Polymerase Chain Reaction (PCR) and Next-Generation Sequencing (NGS)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

IGH Somatic Hypermutation in B-CLL

Aliases
Lists additional common names for a test, as an aid in searching

BCLL

IGVH

IGHV

Next Gen Sequencing Test

Somatic mutation (or Hypermutation)

CLL prognosis

Specimen Type
Describes the specimen type validated for testing

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 is required.. 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, complete blood cell count results and relevant clinical notes), and clinical or morphologic suspicion.

ORDER QUESTIONS AND ANSWERS

Question ID Description Answers
MP005 Specimen Type

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Submit only 1 of the following specimens:

 

Specimen Type: Whole 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 whole blood specimen in original tube. Do not aliquot.

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 bone marrow specimen in original tube. Do not aliquot.

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

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Forms

1. Molecular Hematopathology Patient Information is required.

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

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

Blood/Bone marrow: 1 mL

Extracted DNA: see Specimen Required

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Moderately to severely clotted Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Varies Varies 7 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

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.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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, newly acquired (somatic) point variations are introduced into the variable (V) regions of mature B cells during the germinal center reaction in lymph nodes in a process called somatic hypermutation (SHM). Since chronic lymphocytic leukemia (CLL) originates from the malignant transformation of single lymphoid cells, each daughter cell shares one or, sometimes, more unique "clonal" antigen receptor gene rearrangements, which are cell and 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
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation
Provides information to assist in interpretation of the test results

The presence or absence of somatic hypermutation (SHM) in the immunoglobulin heavy chain gene (IGH) variable (V) region DNA will be reported. A variation frequency of greater than 2% will be reported as mutated. Both the percent mutation and the V region allele identified in the rearrangement will be included in the report.

 

B-cell chronic lymphocytic leukemia (B-CLL) lacking SHM of the IGH V region (unmutated) is associated with a significantly worse prognosis than B-CLL containing SHM of the IGH V region (mutated).

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test is useful for patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) with blood or bone marrow involvement. The prognostic value of somatic IGH V (IGHV) region mutation status is applicable only for this subtype of B-cell malignancy.

 

This test requires a minimum monoclonal CLL B-cell percentage in order to amplify the clonal IGH gene rearrangement. This level has been established at 5% of lymphocytes (eg, as determined by flow cytometric immunophenotyping). A CLL population below 5% will not have a reliable or reproducible clonal gene rearrangement and sequencing by next-generation sequencing to determine somatic mutation status will typically produce no results, or possibly a false-positive finding. Therefore, submitted CLL samples must have a minimum CLL monoclonal B-cell population of 5% of total lymphocytes.

 

The prognostic significance of somatic hypermutation (SHM) status is only known when a single functional IGH rearrangement is identified (ie, in frame junctional coding region with no predicted premature protein truncation). However, a variety of situations can occur, for which the clinical significance is unknown at this time. These can broadly be grouped into the following:

1. Greater than 1 functional rearrangement is identified, with discordant mutation status

2. Only nonfunctional rearrangements are identified

 

Rearrangements with mutation status at or near the 2% cutoff should be interpreted with caution for the purposes of prognosis, particularly if the entire IGHV sequence could not be sequenced due to the use of framework region 1 (FR1) V region primers. If such results are identified, an appropriate comment will be provided in the report.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Davi F, Langerak AW, de Septenville AL, et al. Immunoglobulin gene analysis in chronic lymphocytic leukemia in the era of next generation sequencing. Leukemia. 2020;34(10):2545-2551. doi:10.1038/s41375-020-0923-9

2. Agathangelidis A, Sutton LA, Hadzidimitriou A, et al. Immunoglobulin gene sequence analysis in chronic lymphocytic leukemia: From patient material to sequence interpretation. J Vis Exp. 2018;(141):10.3791/57787. Published 2018 Nov 26. doi:10.3791/57787

3. Rosenquist R, Ghia P, Hadzidimitriou A, et al. Immunoglobulin gene sequence analysis in chronic lymphocytic leukemia: updated ERIC recommendations. Leukemia. 2017;31(7):1477-1481. doi:10.1038/leu.2017.125

Method Description
Describes how the test is performed and provides a method-specific reference

DNA is extracted from whole blood or bone marrow specimens, and IGH gene rearrangements are amplified by polymerase chain reaction (PCR) using indexed leader and/or framework region 1 (FR1) forward primers. The amplified product is then purified, and the DNA concentration measured. Pooled patient samples (identifiable by the index bar codes) are subjected to next-generation sequencing. FASTQC sequence data is subsequently analyzed using proprietary software to identify the IGH V rearrangement and the unique sequence. Results are compared to a germline IGHV sequence database by the software to calculate the percent identity of the tumor IGH V rearrangement to the closest germline sequence. Rearrangements containing a variation frequency of greater than 2% are interpreted as mutated. Rearrangements containing a variation frequency less than or equal to 2% are interpreted as unmutated.(Unpublished Mayo method)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday, Wednesday, Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

14 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

DNA 3 months

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

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

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
BCLL IGH Somatic Hypermutation in B-CLL 50627-9
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
MP005 Specimen Type 31208-2
19674 Final Diagnosis 50398-7
39465 BCLL Result No LOINC Needed

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports