Molecular confirmation of a suspected structural hemoglobinopathy or beta thalassemia.
- Patient Preparation
- Lavender (EDTA) or pink (K2EDTA). Also acceptable: Yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Structural hemoglobinopathies or thalassemias (insufficient or absent beta-chain production).
Incidence: Varies with ethnicity.
Inheritance: Usually autosomal recessive, infrequently autosomal dominant.
Cause: Pathogenic mutations i n the HBB gene.
Mutations tested: The complete protein coding sequence with exon/intron boundaries, proximal promoter, 5' and 3' untranslated regions, and intronic mutations IVS-II-654, IVS-II-705 and IVS-II-745.
Clinical Sensitivity: Up to 97 percent, depending upon ethnicity .
Methodology: Bidirectional sequencing of the HBB coding regions, intron-exon boundaries, proximal promoter, 5' and 3' untranslated regions, and intronic mutations IVS-II-654 , IVS-I I-705 and IVS-II-745.
Analytical sensitivity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Large deletions, and mutations in distal regulatory elements are not detected.
This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|0050578||Beta Globin Full Gene Sequencing||21689-5|
- HBB mutation testing, B Globin gene