Molecular Genetics Laboratory

Laboratory Update

Testing for the Noonan spectrum of disorders is now available at The Children’s Hospital of Philadelphia Molecular Genetics Laboratory.

Alpha Thalassemia (HBA1 and HBA2 Sequence Analysis)

  • Synonyms: Alpha globin gene sequence analysis
  • LIS Mnemonic: MBALPHASEQ

    Collect

    Collect whole blood in a purple top (EDTA) tube.

    Volume Required

    5ml

    Minimum Required

    3ml

    Transport

    Refrigerate sample until shipment. Send the sample at room temperature with overnight delivery for receipt Monday through Friday within 24 hours of collection.

    Stability

    Whole blood can be refrigerated until shipment.

    Unacceptable conditions

    Heparinized specimens, severely hemolyzed specimens, frozen, clotted or possibly commingled specimens, blood in non-sterile or leaky containers, mislabeled or inappropriately labeled specimens.

    Specimen Handling

    Do not heat, freeze or centrifuge blood before shipment. Refrigerate sample until shipment.

Days Performed

Mon - Fri 9:00am to 4:00pm

Reported

2-3 weeks

CPT

81257

Disease Information

Clinical Features:

Autosomal recessive disease caused by deletion or inactivation of one or multiple alpha globin genes. Alpha thalassemia results in anemia, the severity of which depends upon the number of genes that are affected.

Test Methods:

DNA sequence analysis of the alpha 2 globin gene.

Detection Rate:

The analytical sensitivity is close to 100% for point mutations by DNA sequencing.

Utility:

Confirmation of diagnosis, carrier detection, prenatal diagnosis

Remarks

Whole blood in EDTA purple top tubes is the preferred sample. High molecular weight genomic DNA, cheek epithelial cells, or other samples containing DNA may be acceptable. Contact the laboratory for specific instructions regarding such samples before sending the sample.

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