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Alpha-Globin Gene Deletion or Duplication
Test Code16124
CPT Codes
81269
Physician Attestation of Informed Consent
This germline genetic test requires physician attestation that patient consent has been received if ordering medical facility is located in AK, DE, FL, GA, IA, MA, MN, NV, NJ, NY, OR, SD or VT or test is performed in MA.
Preferred Specimen
5 mL whole blood collected in an EDTA (lavender-top) tube
Minimum Volume
3 mL whole blood • 10 mL amniotic fluid • 10 mg chorionic villi
Other Acceptable Specimens
Whole blood collected in: Sodium heparin (green-top) tube or ACD (yellow-top) tube • 10 mL amniotic fluid collected in a sterile plastic leak-proof container • 10 mg chorionic villi collected in a sterile tube filled with sterile culture media • Cultured cells collected in each of two separate sterile T-25 flasks, 75% confluent
Instructions
Do not hold specimen; forward to laboratory when specimen arrives.
Whole blood (preferred): Specimen stability is crucial. Store and ship room temperature immediately. Do not freeze.
For fetal testing:
1) Please call 1-866-GENE-INFO (1-866-436-3463) prior to submission
2) Documentation of parental carrier status must be provided
3) It is required that Maternal Cell Contamination Study, STR Analysis be ordered in conjunction with fetal testing. A separate tube of maternal blood (EDTA) is required for this test.
Amniotic fluid (acceptable): Normal collection procedure. Specimen stability is crucial. Store and ship at room temperature immediately. Do not refrigerate or freeze; forward to laboratory when sample arrives.
Amniocyte or Chorionic Villus (CVS) culture (acceptable): Two sterile T25 flasks, 75% confluent, filled with culture medium. Specimen stability is crucial. Store and ship at room temperature immediately. Do not refrigerate or freeze; forward to laboratory when cells arrive.
Dissected Chorionic Villus (CVS) biopsy (acceptable): 10-20 mg dissected chorionic villi collected in sterile tube, filled with sterile culture medium. Specimen stability is crucial. Store and ship at room temperature immediately. Do not refrigerate or freeze; forward to laboratory when sample arrives.
Whole blood (preferred): Specimen stability is crucial. Store and ship room temperature immediately. Do not freeze.
For fetal testing:
1) Please call 1-866-GENE-INFO (1-866-436-3463) prior to submission
2) Documentation of parental carrier status must be provided
3) It is required that Maternal Cell Contamination Study, STR Analysis be ordered in conjunction with fetal testing. A separate tube of maternal blood (EDTA) is required for this test.
Amniotic fluid (acceptable): Normal collection procedure. Specimen stability is crucial. Store and ship at room temperature immediately. Do not refrigerate or freeze; forward to laboratory when sample arrives.
Amniocyte or Chorionic Villus (CVS) culture (acceptable): Two sterile T25 flasks, 75% confluent, filled with culture medium. Specimen stability is crucial. Store and ship at room temperature immediately. Do not refrigerate or freeze; forward to laboratory when cells arrive.
Dissected Chorionic Villus (CVS) biopsy (acceptable): 10-20 mg dissected chorionic villi collected in sterile tube, filled with sterile culture medium. Specimen stability is crucial. Store and ship at room temperature immediately. Do not refrigerate or freeze; forward to laboratory when sample arrives.
Transport Temperature
Room temperature
Specimen Stability
Whole blood
Room temperature: 30 days
Refrigerated: 30 days
Frozen: 30 days
Amniotic fluid, chorionic villi, cultured cells
Room temperature: 48 hours
Refrigerated: Unacceptable
Frozen: Unacceptable
Room temperature: 30 days
Refrigerated: 30 days
Frozen: 30 days
Amniotic fluid, chorionic villi, cultured cells
Room temperature: 48 hours
Refrigerated: Unacceptable
Frozen: Unacceptable
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Do not reject
Methodology
Capillary Electrophoresis • Multiplex PCR
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Set up: Tues; Report available: 2-3 weeks
Limitations
This test does not identify whether a two-gene deletion is in cis (on the same chromosome) or trans (on opposite chromosomes). In the absence of a coexisting deletion on the opposite chromosome, this test can identify the presence of an extra alpha globin gene (alpha triplication).
Clinical Significance
This test can be used to detect the presence or absence of large deletions in the HBA1 or HBA2 gene in patients or their family members suspected of having alpha-Thalassemia or who are carriers of alpha globin deletions. The assay can also be used in the prenatal diagnosis of alpha-Thalassemia. The assay does not determine the type or breakpoint of the rearrangement. This assay can be used instead of Southern Blot analysis to determine the total number of intact alpha globin genes.