Test Directory

• DiGeorge, TUPLE1 Region, 22q11.2
• 22q13.3 Region

DiGeorge syndrome (DGS) is a primary immunodeficiency disease (PIDD) associated with susceptibility to infections due to decreased T cell production and function due to an absent or poorly developed thymus. Most cases result from a deletion of chromosome 22q11.2 (the DGS chromosome region). The 22q deletion syndrome and 22q duplication syndrome have overlapping phenotypes. Fluorescence in situ hybridization (FISH) studies are highly specific and do not exclude other chromosome abnormalities.

Specimen Types: Leukemic Blood or Bone Marrow

Preferred Collection Container: Green Top (Sodium Heparin)

Alternate Collection Container: Lavendar Top (EDTA)

Desired Specimen Volume: 3 - 5 mL

Minimum Acceptable Volume: 1 mL

• Lithium heparin is not acceptable.
• Specimens must be collected in a sterile collection container.

Each specimen must be accompanied by a requisition form, script, electronic order or physician note. Each order must indicate the reason for testing (diagnosis).

• Transport to the laboratory at room temperature.
• Store specimen as whole blood, in original tube, at room temperature and deliver to lab within 24 hours.
• If specimen cannot be delivered within 24 hours, store in refrigerator. Do not freeze specimen.
• Specimens collected on the weekends must be refrigerated upon arrival at HNL Lab Medicine.

• Specimen frozen
• Specimen arriving without any form of patient identification (unlabeled)
• Specimen with attached needles
• Specimen arriving with broken or leaking collection tube
• Unfixed specimen treated with fixative

In a normal cell, the expected signal pattern is two red signals and two green signals. In an abnormal cell containing the deletion, the expected signal pattern is one red signal and two green signals. In an abnormal cell containing a duplication, the expected signal pattern is three red signals and two green signals.

• FISH DiGeorge
• Deletion 22q