Test Catalog

Test ID: WBDD    
Beta-Globin Cluster Locus, Deletion/Duplication, Varies

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

Determining the etiology of hereditary persistence of fetal hemoglobin (HPFH), or delta-beta-thalassemia


Diagnosing less common causes of beta-thalassemia; these large deletional beta-thalassemia mutations result in elevated hemoglobin (Hb) A2 and usually have slightly elevated Hb F levels


Distinguishing homozygous Hb S disease from a compound heterozygous Hb S/large beta-globin cluster deletion disorder (ie, Hb S/beta zero thalassemia, Hb S/delta beta zero thalassemia, Hb S/HPFH, Hb S/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 Hb F 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 Hb P-Nilotic


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


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 nondeletional hereditary persistence of fetal hemoglobin.

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 beta-globin cluster locus deletion and duplication testing because these conditions can be complex and protein data allows accurate classification of the patient phenotype.


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

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

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 (HPFH), delta-beta-thalassemias, and gamma-delta-beta-thalassemia

-Identifying beta-thalassemia conditions in cases where beta gene sequencing did not find a beta-thalassemia mutation

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

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

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

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

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) 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.


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

Beta Globin Cluster Locus Del/Dup

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

MLPA beta globin cluster locus
Beta globin cluster locus deletion/duplication
Beta globin deletion
Beta thalassemia deletion
Beta globin complex deletions
Beta cluster del/dup