Lab Information Manual

Laboratory:

Genomics

Test Name:

ALPHA THALASSEMIA - HBA1 GENE, HBA2 GENE - (B)

Test Code: MD

Clinical Information:

Hemoglobinopathy investigation is required prior to or concurrently with molecular diagnostic testing. Testing is generally limited to 7 common deletions of the HBA1 and HBA2 genes, these are -α^3.7(3.7-kb deletion of HBA2), -α^4.2 (4.2-kb deletion of HBA2), -α^20.5 (20.5-kb deletion of HBA2 & 5' end of HBA1), ^--SEA (~20-kb deletion incl both HBA2 & HBA1on same chromosome), --FIL (~30-kb deletion incl HBZ, HBA2, & HBA1on same chromosome), --THAI(~34-kb deletion involving HBZ, HBA2, & HBA1on same chromosome), and –MED (~26-kb deletion involving HBZ, HBA2, & HBA1on same chromosome).

Testing for carrier status is restricted to Medical Genetics for reproductive risk assessment in couples with abnormal hemoglobinopathy.

Testing symptomatic patients is restricted to hematologists or an appropriate specialist.

For more information, see http://www.ncbi.nlm.nih.gov/books/NBK1435/

Collection Devices:

Preferred Device:	2 - EDTA 4 mL NO GEL Tube(s) - Full Tube Collection EDTA 4 mL NO GEL Tube(s) - Full Tube Collection Manufacturer: Becton Dickinson & Company Catalogue #: 367861
Alternate Device:	6 - Microtainer(s) - EDTA, NO GEL (0.5 mL) to fill line Microtainer(s) - EDTA, NO GEL (0.5 mL) to fill line Manufacturer: Becton Dickinson & Company Catalogue #: 363706 - Quantity: 2-6 Microtainer for pediatric samples only. For prenatal diagnosis, contact laboratory Genetic Counsellor for prior approval and to obtain specimen requirements.

Specimen Required:

Whole Blood: 8.0 mL

Pediatric Whole Blood: 3.0 mL

Pediatric Volume: 1-3 mL

Specimen Handling: Do NOT centrifuge. Forward specimen to Health Sciences Centre MS551.

Preferred - Store and ship specimens at room temperature.

Refrigerated: Accepted

Frozen: Accepted - must remain frozen

Other comments: Specimens sent for Molecular tests are not to be used for other tests (i.e., CBC).

Referral:

Requisition:

_SH Molecular Diagnostic Laboratory Out of Centre Genetic Test Requisition (R250-10-103)

Reference Values:

An interpretive report from the referral laboratory will be forwarded to the physician.

Availability:

Availability: Turnaround time (TAT) As per the referral laboratory.