RNA-based Known Variant Testing (RT2)
Information for Ordering
Acceptable Specimen Types
- Fresh blood sample: 3–6 mL EDTA; must be received within 60–72 hours of collection
Whole blood specimens submitted for RNA-based testing must be received within 60–72 hours of collection to maintain lymphocyte viability.
Turnaround Time
Average turnaround time: 22 working days
Price, CPT Codes, and Z Code
- Institutional/self-pay price: $500 USD
- CPT codes: 88230 and 81403
- Z code: ZB68I
Candidates for Testing
Patients with a variant of uncertain significance identified by next-generation sequencing that is predicted to affect splicing; patients preparing for prenatal or preimplantation genetic testing; and individuals at risk of inheriting a previously identified variant in the NF1 or NF2 gene.
Specimen Shipping and Handling
Please refer to the specimen requirements listed above.
All submitted specimens must be shipped at room temperature. Do not ship specimens on ice.
Because this specimen must be received within 60–72 hours of collection, please plan shipment carefully and avoid delays that could affect specimen viability.
Specimens must be packaged to prevent breakage. Absorbent material must be included to contain liquids if breakage occurs. Specimens must also be shipped in double watertight containers, such as a specimen pouch placed inside the shipping company’s diagnostic envelope.
To request a collection kit, please complete the Collection Kit Request Form .
Before shipping a specimen, please contact the UAB Medical Genomics Laboratory by email at medgenomics@uabmc.edu or by phone at 205-934-5562. Please provide the collection date, shipment date, and package tracking number so the laboratory can help ensure timely receipt.
Required Forms
Other phenotypic checklists:
- NF2 and Schwannomatosis Phenotypic Checklist
- SMARCB1 / ATRT Phenotypic Checklist
- TSC Phenotypic Checklist
- PTEN Phenotypic Checklist
About
Test Description
For RNA-based testing, a whole blood specimen must be submitted in an EDTA collection tube and received within 60–72 hours of collection to maintain lymphocyte viability.
We offer targeted detection of a previously characterized familial variant. From a fresh EDTA blood specimen, RNA and/or DNA analysis is performed to evaluate the target region and determine the effect of the known variant. To offer this testing service, the proband’s variant must have been identified by our laboratory before testing relatives.
Important Information Regarding NF1
With the largest dataset of NF1 genotypes matched with phenotypes, identified genotype-phenotype correlations will be reported as applicable. Confirmatory testing of reportable variants is performed using orthogonal methods as needed.
For novel NF1 variants of uncertain significance, targeted RNA-based testing may be offered at no charge to assess the effect of the variant on splicing and support accurate classification and interpretation.
Relevant family members of a proband with a novel or previously identified variant of uncertain significance may be offered targeted analysis at no charge when accurate phenotypic information is provided by a healthcare professional. There is no set limit on the number of relatives who may be tested in qualifying families.
Mosaicism is often present in sporadic patients with an NF1 microdeletion and may have important implications for genetic counseling. Evaluation by FISH analysis may be offered in these cases.
View references for this testing .
Other Related Test Options
- Prenatal Known Variant Testing (PT2)
- Known Variant Testing (KT2)
- Next-Generation Sequencing-Based Known Variant Testing (KT2-NG)
For more information, test requisition forms, or collection kits, please contact the UAB Medical Genomics Laboratory at 205-934-5562 or medgenomics@uabmc.edu.