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 -α3.7 (3.7-kb deletion of HBA2), -α4.2 (4.2-kb deletion of HBA2), -α20.5 (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:
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:
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.
See Also:
More Information:
Do NOT centrifuge.  Ship blood samples at room temperature to Health Sciences Centre - MS5.  Extracted DNA will be forwarded for testing to a reference laboratory.  Specimen sent for Molecular tests are not to be used for other tests (ie. CBC).