Alpha-Globin Gene Deletion or Duplication

Test Code

16124

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.

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

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 following set up

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).

Reference Range

See Laboratory Report

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.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.