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Test Code WASEQ Alpha Globin Gene Sequencing, Varies

Useful For

Diagnosing nondeletional alpha thalassemia

 

Testing for nondeletional alpha thalassemia in a symptomatic individual

 

Follow-up testing to an abnormal hemoglobin electrophoresis that identified an alpha-globin chain variant

Genetics Test Information

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

 

Not the preferred first-tier molecular test for carrier screening or diagnosis of alpha thalassemia. This test is used to identify nondeletional alpha-thalassemia variants when there is a strong clinical suspicion and AGDD / Alpha Globin Cluster Locus Deletion/Duplication, Varies is negative. This test can also identify alpha-globin variants that can result in variable phenotypes, such as erythrocytosis, chronic hemolytic anemia, and many that are clinically benign.

Method Name

Polymerase Chain Reaction (PCR)/ Sanger Sequencing

Reporting Name

Alpha Globin Gene Sequencing, B

Specimen Type

Varies


Ordering Guidance


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

 

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

 

If genetic testing is desired, the first-tier genetic test assesses large deletional alpha-thalassemia alterations. Order AGDD / Alpha Globin Cluster Locus Deletion/Duplication, Varies.



Necessary Information


1. Patient's age is required.

2. Include recent transfusion information.



Specimen Required


Submit only 1 of the following specimens:

 

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

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
Varies Varies

Reject Due To

Gross hemolysis OK
Moderately to severely clotted Reject

Reference Values

An interpretive report will be provided.

Day(s) Performed

Monday through Friday

Report Available

10 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

81259-HBA1/HBA2; full sequence

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)

3. If not ordering electronically, complete, print, and send Benign Hematology Test Request Form (T755) with the specimen