Confirmatory genetic test on fetal samples for the prenatal detection of structural hemoglobinopathies and beta thalassemia.
- Patient Preparation
- Fetal Specimen: Two T-25 flasks at 80% confluent of cultured amniocytes. If the client is unable to culture amniocytes, this can be arranged by contacting ARUP Client Services at (800) 522-2787. Or amniotic fluid.
AND Maternal Cell Contamination Specimen: Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
OR Whole Blood in lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Cultured Amniocytes: Fill flasks with culture media. Transport two T-25 flasks at 80% confluent of cultured amniocytes filled with culture media. Backup cultures must be retained at the client's institution until testing is complete.
OR Amniotic Fluid: Transport 10 mL unspun fluid. (Min: 5 mL)
AND Maternal Cell Contamination Specimen: Transport 3 mL whole blood (Min: 1 mL)
OR Whole Blood: Transport 3 mL whole blood (Min: 1 mL)
- Storage/Transport Temperature
- Cultured Amniocytes: CRITICAL ROOM TEMPERATURE. Must be received within 48 hours of shipment due to liability of cells.
Amniotic fluid: Room temperature.
Whole Blood or Maternal Cell Contamination Specimen: Room temperature.
- Unacceptable Conditions
- Maternal specimen is recommended for proper test interpretation. Order Maternal Cell Contamination. Patient History Form is available on the ARUP Web site or by contacting ARUP Client Services.
- Fetal Specimen: Ambient: 48 hours; Refrigerated: Unacceptable; Frozen: Unacceptable
Whole Blood or Maternal Cell contamination Specimen: 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 in the HBB gene.
Clinical Sensitivity: Up to 97 percent, depending upon ethnicity.
Methodology: Bidirectional sequencing of the HBBcoding regions, intron-exon boundaries, proximal promoter, 5' and 3' untranslated regions, and intronic mutations IVS-II-654, IVS-II-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.
For quality assurance purposes, ARUP Laboratories will confirm the above result at no charge following delivery. Order Confirmation of Fetal Testing and include a copy of the original fetal report (or the mother's name and date of birth) with the test submission. Please contact an ARUP genetic counselor at (800) 242-2787 extension 2141 prior to specimen submission.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|0050548||Maternal Contamination Study Fetal Spec||31208-2|
|0050612||Maternal Contam Study, Maternal Spec||31208-2|
|0051366||BGSEQ FE Specimen|
|2013108||BESEQ FE, Interpretation|
- Carrier testing Beta thalassemia
- Fetal HBB mutation testing