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Test Code WBGDD Beta-Globin Gene Cluster, Deletion/Duplication, 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


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


Secondary ID

620979

Useful For

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.

Method Name

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

Reporting Name

Beta Globin Gene Cluster, Del/Dup,V

Specimen Type

Varies

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reject Due To

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

Day(s) Performed

Wednesday, Friday

Report Available

25 to 30 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. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

81363-HBB (hemoglobin, beta, beta-globin) (e.g. beta thalassemia), duplication/deletion analysis

LOINC Code Information

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
620981 Beta Globin Gene Cluster Del/Dup 101634-4
620982 Specimen 31208-2
620983 Reviewed by 18771-6
620980 Interpretation 69047-9

Reference Values

An interpretive report will be provided