Test Details
Methodology
DNA sequencing
Result Turnaround Time
50 - 63 days
Use
Confirm a clinical diagnosis of SCID; detect carriers; allow early diagnosis in family members
Special Instructions
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.
Specimen Requirements
Test Includes
This test covers all coding nucleotides of genes RAG1 and RAG2, 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.
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.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration
This method does not reliably detect mosaic variants; large deletions; large duplications, inversions 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. |
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. This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration |
References
Custom Additional Information
Severe combined immunodeficiency (SCID) is a recessively (X-linked or autosomal) inherited immune disorder characterized by severe lymphopenia and lack of adaptive immunity, leading to severe and persistent infections. Left untreated, SCID is typically lethal in infancy or childhood. T-cell lymphopenia is common to all forms of SCID, but may be initially masked by the temporary presence of maternal lymphocytes that have crossed the placenta during gestation. Levels of B cells and of natural killer (NK) cells vary depending on the genetic defect. Mutations in RAG1 or RAG2 cause T-B-NK+SCID with autosomal recessive inheritance and account for about 3% of SCID overall. Mutations in RAG1 and RAG2 that show residual activity lead to Omenn syndrome, which can be distinguished from SCID by the presence of normal or elevated T-cell levels, elevated levels of serum IgE, and eosinophilia. In rare cases, B cells are also present; however, both B cells and T cells are oligoclonal and nonfunctional. Genetic testing can confirm a clinical diagnosis of RAG1 or RAG2-related SCID and detect mutation carriers within affected families.
Specimen
Whole blood; DNA is accepted (Call 800-345-4363 for DNA collection information.)
Volume
2 mL
Container
Lavender-top (EDTA) tube
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Container broken or leaking; container not labeled or label not legible; use of improper anticoagulant
Collection Instructions
Samples may be stored for brief periods at 4°C. Ship overnight at room temperature.
Reference Range
Normal equals reference sequence or variants that are known or predicted to be benign; abnormal equals all other variants.
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 252499 | SCID:RAG1/RAG2 | 41103-3 | 252170 | Routing | 41103-3 | |
| Order Code | 252499 | |||||
| Order Code Name | SCID:RAG1/RAG2 | |||||
| Order Loinc | 41103-3 | |||||
| Result Code | 252170 | |||||
| Result Code Name | Routing | |||||
| UofM | ||||||
| Result LOINC | 41103-3 |