Test Catalog

Test ID: WASEQ    
Alpha Globin Gene Sequencing, Blood

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

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

A hemoglobin electrophoresis evaluation (HBELC / Hemoglobin Electrophoresis Cascade, 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. DNA sequencing of HBA1/HBA2 (alpha globin 1 and alpha globin 2) is used to identify nondeletional alpha-thalassemia mutations when there is a strong clinical suspicion and ATHAL / Alpha-Globin Gene Analysis, 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.

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test is a second-tier test in the evaluation of alpha thalassemia carrier determination, hemoglobin H disease confirmation, and alpha globin variant identification.   First-tier testing for alpha thalassemia detection is THEVP / Thalassemia and Hemoglobinopathy Evaluation. If only genetic testing is desired, the first-tier genetic test is for large deletional alpha thalassemia mutations (ATHAL / Alpha-Globin Gene Analysis). First-tier testing for an alpha globin variant is HBELC / Hemoglobin Electrophoresis Cascade, Blood.

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

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

Polymerase Chain Reaction (PCR) followed by DNA Sequence Analysis

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

Alpha Globin Gene Sequencing, B

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

Alpha Globin
Alpha Thalassemia
HBA1
HBA2
HB Barts
HB H Disease
Alpha-thalassemia
Hydrops Fetalis
Thalassemia, Alpha
Hemoglobin variant, Alpha
Alpha Globin Sequencing
Alpha Hemoglobin