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For hours, walk-ins and appointments.Common Variable Immunodeficiency Syndrome (CVID): TNFRSF13B (TACI) (Full Gene Sequencing)
CPT:
81479
Test Includes
This test covers all coding nucleotides of gene TNFRSF13B (TACI), plus at least two and typically 20 flanking intronic nucleotides upstream and downstream of each coding exon, covering the conserved donor and acceptor splice sites, as well as typically 20 flanking nucleotides in the 5′ and 3′ UTR.
Special Instructions
In cases in which a known mutation can be documented, the physician may prefer to order test 252687.
Test orders must include an attestation that the provider has the patient's informed consent for genetic testing. See sample physician office consent form: Consent for Genetic Testing. In the case of family tests (ie, known mutations), please submit the result report of the first patient tested in the family (the index case), if not performed at a LabCorp facility. Other family members are subsequently tested for the specific mutation found in the first patient tested.
Expected Turnaround Time
21 - 35 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Specimen Requirements
Specimen
Whole blood; DNA is accepted (Call 800-345-4363 for DNA collection information.)
Volume
2 mL
Container
Lavender-top (EDTA) tube
Collection
Samples may be stored for brief periods at 4°C. Ship overnight at room temperature.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Container broken or leaking; container not labeled or label not legible; improper anticoagulant
Test Details
Use
Confirm a clinical diagnosis of TACI; allow early diagnosis in family members, guiding prophylactic measures
Limitations
This method does not reliably detect mosaic variants; large deletions; large duplications, inversions, or other rearrangements; or deep intronic variants. It may be affected by allele-dropout, it may not allow determination of the exact numbers of T/A or microsatellite repeats, and it does not allow any conclusion as to whether two heterozygous variants are present on the same or on different chromosome copies.
Results of this test are for investigational purposes only. The performance characteristics of this assay have been determined by LabCorp. The result should not be used as a diagnostic procedure without confirmation of the diagnosis by another medically established diagnostic product or procedure.
Methodology
DNA sequencing
Reference Interval
Normal equals reference sequence or variants that are known or predicted to be benign; abnormal equals all other variants.
Additional Information
Common variable immunodeficiency (CVID) is a heterogeneous immune disorder characterized by low levels of IgA and, sometimes, also IgG and/or IgM, leading to increased susceptibility to bacterial infections. Inflammatory bowel disease and chronic diarrhea due to infection with intestinal parasites are also common, and about 20% of patients suffer from autoimmune diseases. In addition, risk of malignant lymphoma is increased. About 10% of patients with CVID harbor mutations in the gene TNFRSF13B (also called TACI), which are believed to confer a strong predisposition for CVID, with widely varying penetrance. Genetic testing can confirm a clinical diagnosis of XLA and detect mutation carriers within affected families.
References
Castigli E, Geha RS. Molecular basis of common variable immunodeficiency. J Allergy Clin Immunol. 2006 Apr; 117(4):740-746.16630927
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 252456 | CVID: TNFRSF13B (TACI) | 57758-5 | 252184 | Routing | 57758-5 |
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