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Test ID WBSEQ Beta Globin Gene Sequencing, Varies

Useful For

Diagnosis of beta thalassemia intermedia or major

 

Identification of a specific beta thalassemia sequence variant (ie, unusually severe beta thalassemia trait)

 

Evaluation of an abnormal hemoglobin electrophoresis identifying a rare beta-globin variant

 

Evaluation of chronic hemolytic anemia of unknown etiology

 

Evaluation of hereditary erythrocytosis with left-shifted p50 oxygen dissociation results

 

Preconception screening when there is a concern for a beta-hemoglobin disorder based on family history

Genetics Test Information

Beta-globin gene (HBB) sequencing can be used to identify hemoglobin variants and the most common beta thalassemia sequence variants, including beta plus and beta zero thalassemias. It also identifies hyper-unstable hemoglobin variants and dominant beta thalassemia sequence variants, as well as other hemoglobin variants that cannot be identified by protein methods. Some hemoglobin disorders will not be detected by beta-globin gene sequencing, such as large deletional alterations and crossover events. As such, the results of this test should always be interpreted within the context of the protein studies and red blood cell indices.

Testing Algorithm

A hemoglobin electrophoresis evaluation (HBEL1 / Hemoglobin Electrophoresis Evaluation, Blood) is always indicated prior to beta-globin gene sequencing because these conditions can be complex and protein data allows accurate and rapid classification of the patient phenotype.

Method Name

Polymerase Chain Reaction (PCR)/Sanger Sequencing

Reporting Name

Beta Globin Gene Sequencing, B

Specimen Type

Varies


Ordering Guidance


For first-tier testing for beta thalassemia, order THEV1 / Thalassemia and Hemoglobinopathy Evaluation, Blood and Serum.

 

For first-tier testing for beta-globin variant detection, order HBEL1 / Hemoglobin Electrophoresis Evaluation, Blood.



Necessary Information


1. Patient's age is required.

2. Include recent transfusion information.



Specimen Required


Specimen Type: Peripheral blood

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD), green top (sodium heparin)

Specimen Volume: 4 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in the original tube.

Specimen Stability Information: Refrigerate 30 days(preferred)/Ambient 14 days

 

Specimen Type: Extracted DNA from whole blood

Container/Tube: 1.5- to 2-mL tube

Specimen Volume: Entire specimen

Collection Instructions:

1. Label specimen as extracted DNA and source of specimen

2. Provide volume and concentration of the DNA

Specimen Stability Information: Frozen (preferred)/Refrigerate/Ambient


Specimen Minimum Volume

Blood: 1 mL
Extracted DNA: 50 mcL at 50 ng/mcL concentration

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reference Values

An interpretive report will be provided.

Day(s) Performed

Monday through Friday

Report Available

2 to 10 days

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 US Food and Drug Administration.

CPT Code Information

81364-HBB (hemoglobin, beta) full sequence

LOINC Code Information

Test ID Test Order Name Order LOINC Value
WBSEQ Beta Globin Gene Sequencing, B 79401-6

 

Result ID Test Result Name Result LOINC Value
62128 Beta Globin Gene Sequencing, B 82939-0
43922 Interpretation 69047-9

NY State Approved

Yes

Forms

1. 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 in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Metabolic Hematology Patient Information (T810) in Special Instructions

Highlights

This is a second-tier evaluation of beta thalassemia minor, intermedia, and major, as well as beta-globin variant identification.