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HelpTest Code WBDD Beta-Globin Cluster Locus, Deletion/Duplication, Varies
Reporting Name
Beta Globin Cluster Locus Del/DupPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
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 variants result in elevated hemoglobin (Hb) A2 and usually have slightly elevated HbF levels
Distinguishing homozygous Hb S disease from a compound heterozygous HbS/large beta-globin cluster deletion disorder (ie, HbS/beta zero thalassemia, Hb S/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 HbA2 percentages
Confirming gene fusion hemoglobin variants such as Hb Lepore and Hb P-Nilotic
Confirming homozygosity vs hemizygosity of variants 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 HPFH.
Method Name
Polymerase Chain Reaction (PCR) Analysis/Multiplex Ligation-Dependent Probe Amplification (MLPA)
Ordering Guidance
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; see Special Instructions. 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
Collection Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable:Â Yellow top (ACD)
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: Refrigerated: 30 days; Ambient: 8 hours
Specimen Type
VariesSpecimen 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.Reference Values
An interpretive report will be provided.
Day(s) Performed
Wednesday, Friday
Report Available
25 to 30 daysTest 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) (eg, beta thalassemia), duplication/deletion analysis
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| WBDD | Beta Globin Cluster Locus Del/Dup | 101634-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 48361 | Beta Globin Cluster Locus Del/Dup | 50397-9 |
| 48438 | Specimen | 31208-2 |
| 48360 | Reviewed by | 18771-6 |
| 48362 | Interpretation | 69047-9 |
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. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
Metabolic Hematology Patient Information (T810) is required.
Testing Algorithm
A hemoglobin electrophoresis evaluation (HBEL1 / Hemoglobin Electrophoresis Evaluation, Blood) is always indicated prior to beta-globin cluster locus deletion and duplication testing as these conditions can be complex and protein data allows accurate classification of the patient phenotype.