Beta Globin (HBB) Sequencing, Fetal

Casandra

Casandra Test Code AR64489Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 3004550CPT Codes 81265, 81364

Beta Globin (HBB) Sequencing, Fetal

Also known as: BG NGS FE

Clinical Use

Order Test

Use

Beta thalassemia is caused by decreased or absent synthesis of the hemoglobin beta chain resulting in variable clinical presentations ranging from mild anemia to transfusion dependence. Structural hemoglobinopathies can cause sickling disorders, microcytic or hemolytic anemia, cyanosis, or erythrocytosis. This test is used for molecular confirmation of suspected structural hemoglobinopathies or beta thalassemia in fetal samples. Pathogenic germline variants within the HBB gene are the cause. The test is not intended to detect all HBB variants.

Special Instructions

Submit a Non-Permitted Laboratory Request Form (NPL) to the NYDOH prior to the collection of specimen if testing is intended for New York patients. A fetal molecular testing patient history form and informed consent for genetic testing are required for NY patients.

Limitations

A negative result does not exclude beta thalassemia as not all HBB variants are detected by this assay. The test detects variants within coding regions and intron-exon boundaries of the HBB gene. Deletions/duplications/insertions of any size may not be detected by massively parallel sequencing. Large deletions/duplications, regulatory region variants upstream of c.-250, deep intronic variants (other than those specified), and noncoding transcripts will not be identified. Diagnostic errors may occur due to rare sequence variations. Variants in some regions may not be detected due to technical limitations, pseudogenes, repetitive, or homologous regions.

Test Details