Test Catalog

Test Id : WBGDD

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Beta-Globin Gene Cluster, Deletion/Duplication, Varies

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Overview

Test Catalog

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

Determining the etiology of hereditary persistence of fetal hemoglobin (HPFH), delta-beta thalassemia, or other large deletions involving the beta-globin gene cluster

 

Diagnosing less common causes of beta thalassemia; these large deletional beta-thalassemia variants result in elevated hemoglobin (Hb) A2 and can have elevated HbF levels

 

Distinguishing homozygous HbS disease from a compound heterozygous HbS/large beta-globin cluster deletion disorder (ie, HbS/beta zero thalassemia, HbS/delta-beta zero thalassemia, HbS/HPFH, HbS/gamma-delta-beta thalassemia)

 

Diagnosing complex thalassemias where the beta-globin gene and one or more of the other genes in the beta-globin cluster have been deleted

 

Evaluating and classifying unexplained increased HbF percentages

 

Evaluating microcytic neonatal anemia

 

Evaluating unexplained long standing microcytosis in the setting of normal iron studies and negative alpha-thalassemia testing/normal Hb A2 percentages

 

Confirming gene fusion hemoglobin variants such as Hb Lepore and HbP-Nilotic

 

Confirming homozygosity vs hemizygosity of variants in the beta-like genes (HBB, HBD, HBG1, HBG2)

 

Investigating newborns with HbA levels greater than HbF on newborn screen in the absence of transfusion

 

This test is not useful for diagnosis or confirmation of alpha thalassemia, the most common beta thalassemias, or hemoglobin variants. It also does not detect non-deletional HPFH.

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test can be used to identify a variety of conditions (see Highlights) that involve large deletions of the beta-globin gene cluster. These alterations will not be detected by DNA sequencing of the beta-globin gene.

Highlights

This test is recommended to identify a variety of conditions involving large deletions or duplications within the beta-globin gene cluster locus region including:

-Identifying large deletions causing increased hemoglobin (Hb) F levels, such as hereditary persistence of fetal hemoglobin, delta-beta thalassemias, and gamma-delta-beta thalassemia

-Identifying large deletions associated with elevated HbA2, such as beta-thalassemia (or rarely epsilon-gamma thalassemia) in cases where beta gene sequencing did not find a beta thalassemia variant

-Confirming gene fusion hemoglobin variants, such as Hb Lepore and HbP-Nilotic

-Investigating newborns and adults with unexplained microcytic anemia that is suspected to be caused by epsilon-gamma-delta-beta thalassemia

-Confirming homozygosity vs hemizygosity of variants in the beta-like genes (HBB, HBD, HBG1, HBG2)

-Investigating individuals older than 12 months with unexplained microcytosis and normal hemoglobin electrophoresis for whom more common causes of microcytosis, such as iron deficiency and alpha thalassemia have been excluded

-Investigating newborns with HbA levels greater than HbF on newborn screen in the absence of transfusion

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

Polymerase Chain Reaction (PCR) Analysis/Multiplex Ligation-Dependent Probe Amplification (MLPA)

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

Beta Globin Gene Cluster, Del/Dup,V

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

Beta cluster del/dup

Beta globin cluster locus deletion/duplication

Beta globin complex deletions

Beta globin deletion

Beta thalassemia deletion

BGLOB

Specimen Type
Describes the specimen type validated for testing

Varies

Additional Testing Requirements

Hemoglobin electrophoresis studies performed at Mayo Clinic Laboratories are highly recommended prior to this test to allow for more complete interpretation of results. See HBEL1 / Hemoglobin Electrophoresis Evaluation, Blood or THEV1 / Thalassemia and Hemoglobinopathy Evaluation, Blood and Serum.

Shipping Instructions

Specimens must arrive within 4 days (96 hours) of collection.

Necessary Information

Metabolic Hematology Patient Information (T810) is required. Send a completed form with the specimen. Document the reason for suspecting a large beta cluster locus deletion along with the hemoglobin F percentage and red blood cell indices for the patient.

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

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 specimen in the original tube. Do not aliquot.

Specimen Stability Information: Refrigerated (preferred)/Ambient

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

Forms

1. Metabolic Hematology Patient Information (T810) is required.

2. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

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.

2 mL

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

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

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

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

Determining the etiology of hereditary persistence of fetal hemoglobin (HPFH), delta-beta thalassemia, or other large deletions involving the beta-globin gene cluster

 

Diagnosing less common causes of beta thalassemia; these large deletional beta-thalassemia variants result in elevated hemoglobin (Hb) A2 and can have elevated HbF levels

 

Distinguishing homozygous HbS disease from a compound heterozygous HbS/large beta-globin cluster deletion disorder (ie, HbS/beta zero thalassemia, HbS/delta-beta zero thalassemia, HbS/HPFH, HbS/gamma-delta-beta thalassemia)

 

Diagnosing complex thalassemias where the beta-globin gene and one or more of the other genes in the beta-globin cluster have been deleted

 

Evaluating and classifying unexplained increased HbF percentages

 

Evaluating microcytic neonatal anemia

 

Evaluating unexplained long standing microcytosis in the setting of normal iron studies and negative alpha-thalassemia testing/normal Hb A2 percentages

 

Confirming gene fusion hemoglobin variants such as Hb Lepore and HbP-Nilotic

 

Confirming homozygosity vs hemizygosity of variants in the beta-like genes (HBB, HBD, HBG1, HBG2)

 

Investigating newborns with HbA levels greater than HbF on newborn screen in the absence of transfusion

 

This test is not useful for diagnosis or confirmation of alpha thalassemia, the most common beta thalassemias, or hemoglobin variants. It also does not detect non-deletional HPFH.

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test can be used to identify a variety of conditions (see Highlights) that involve large deletions of the beta-globin gene cluster. These alterations will not be detected by DNA sequencing of the beta-globin gene.

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

Large deletions involving the beta-globin cluster locus on chromosome 11 manifest with widely variable clinical phenotypes. Up to 10% of beta-thalassemia cases (dependent on ethnicity) are caused by large deletions in the beta-globin cluster. Other thalassemias including delta-beta thalassemia, gamma-delta-beta-thalassemia, epsilon gamma thalassemia, and epsilon-gamma-delta-beta-thalassemia, also result from functional loss of genes or the locus control region that controls globin gene expression. In addition, hereditary persistence of fetal hemoglobin (HPFH) is caused by deletions of variable size along the beta-globin cluster locus. Most, but not all, of the large deletion beta-globin cluster disorders are associated with variably elevated hemoglobin F percentages that persist after 2 years of age. In addition, many manifest in microcytosis. A notable exception is HPFH, which can have normal to minimal decreased mean corpuscular volume values. The correct classification of these deletions is important as they confer variable predicted protective phenotypes, and some are more protective than others when found in combination with a second beta-globin variant, such as HbS or beta thalassemia. In addition, identification of these deletions can explain lifelong microcytosis in the setting of normal iron studies and negative alpha thalassemia molecular results.

Interpretation
Provides information to assist in interpretation of the test results

The alterations will be provided with the classification that fits the probe pattern, if known. Further interpretation requires correlation with protein studies and red blood cell indices.

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

Non-deletional subtypes of beta thalassemia or hereditary persistence of fetal hemoglobin are not detected by this assay. In addition to disease-related probes, the multiplex ligation-dependent probe amplification technique utilizes probes localized to other chromosomal regions as the internal controls. In certain circumstances, these control probes may detect other diseases or conditions for which this test was not specifically intended. Results of the control probes are not normally reported. However, in cases where clinically relevant information is identified, the ordering physician will be informed of the result and provided with recommendations for any appropriate follow-up testing.

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

1. Hein MS, Oliveira JL, Swanson KC, et al. Large deletions involving the beta globin gene complex: genotype-phenotype correlation of 119 cases. Blood. 2015;126(23):3374

2. Kipp BR, Roellinger SE, Lundquist PA, Highsmith WE, Dawson DB. Development and clinical implementation of a combination deletion PCR and multiplex ligation-dependent probe amplification assay for detecting deletions involving the human alpha-globin gene cluster. J Mol Diagn. 2011;13(5):549-557. doi:10.1016/j.jmoldx.2011.04.001

3. Rund D, Rachmilewitz E. Beta-thalassemia. N Engl J Med. 2005;353(11):1135-1146

4. Nussbaum R, McInnes R, Willard H. Principles of molecular disease: Lessons from the hemoglobinopathies. In: Thompson and Thompson Genetics in Medicine. 7th ed. Saunders Elsevier; 2007:323-342

5. Wood WG. Hereditary persistence of fetal hemoglobin and delta beta thalassemia. In: Steinberg MH, Forget BG, Higgs DR, Nagel RL, eds. Disorders of Hemoglobin: Genetics, Pathophysiology, and Clinical Management. Cambridge University Press, 2001;356-388

6. Oliveira JL, Thompson CH, Saravanaperumal SA, et al. eg-Thalassemia, a new hemoglobinopathy category. Clin Chem. 2023;69(7):711-717. doi:10.1093/clinchem/hvad038

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

Multiplex ligation-dependent probe amplification is utilized to test for the presence of large deletions or duplications in the beta-globin gene.(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.

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.

25 to 30 days

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

Whole blood: 2 weeks; 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.

81363-HBB (hemoglobin, beta, beta-globin) (e.g. beta thalassemia), duplication/deletion 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
WBGDD Beta Globin Gene Cluster, Del/Dup,V 101634-4
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.
620981 Beta Globin Gene Cluster Del/Dup 101634-4
620982 Specimen 31208-2
620983 Reviewed by 18771-6
620980 Interpretation 69047-9

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

Test Update Resources

Change Type Effective Date
New Test 2024-12-19