TTR Gene, Full Gene Analysis (Sendout)

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General Information

Lab Name
Lab Code
118
External Test Id
TTRZ
Description

Useful For:

  • Establishing a molecular diagnosis for patients with amyloidosis
  • Identifying variants within TTR known to be associated with amyloidosis, allowing for predictive testing of at-risk family members
  • This test utilizes next-generation sequencing to detect single nucleotide and copy number variants in one gene associated with amyloidosis, TTR.
Synonyms
AMYL, Familial Amyloidosis DNA Sequence, Transthyretin (TTR) Gene, Transthyretin DNA, TTR (Transthyretin) Gene, TTRZ

Interpretation

Method

Sequence Capture and Targeted Next-Generation Sequencing followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing

Interferences and Limitations

Clinical Cautions:

  • Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Misinterpretation of results may occur if the information provided is inaccurate or incomplete.
  • If testing was performed because of a clinically significant family history, it is often useful to first test an affected family member. Detection of a reportable variant in an affected family member would allow for more informative testing of at-risk individuals.
  • To discuss the availability of additional testing options or for assistance in the interpretation of these results, contact the Mayo Clinic Laboratories genetic counselors at 800-533-1710.

Technical Limitations:

  • Next-generation sequencing may not detect all types of genomic variants. In rare cases, false-negative or false-positive results may occur. The depth of coverage may be variable for some target regions; assay performance below the minimum acceptable criteria or for failed regions will be noted. Given these limitations, negative results do not rule out the diagnosis of a genetic disorder. If a specific clinical disorder is suspected, evaluation by alternative methods can be considered.
  • There may be regions of genes that cannot be effectively evaluated by sequencing or deletion and duplication analysis as a result of technical limitations of the assay, including regions of homology, high guanine-cytosine (GC) content, and repetitive sequences. Confirmation of select reportable variants will be performed by alternate methodologies based on internal laboratory criteria.
  • This test is validated to detect 95% of deletions up to 75 base pairs (bp) and insertions up to 47 bp. Deletions-insertions (delins) of 40 or more bp, including mobile element insertions, may be less reliably detected than smaller delins.

A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.

Ordering & Collection

Specimen Type
Blood
Collection

3 mL blood in LAVENDER (EDTA) or YELLOW TOP (ACD) tube

Handling Instructions

Outside Laboratories:

  • Store and transport whole blood at ambient temperature.
  • Expedite transport. Specimen must be received at Mayo Clinic Labs within 96 hours of collection (allow for transport time from UW-MT lab to Mayo).

Stability: Ambient (preferred): 96 hours; Refrigerated: 96 hours; Frozen: Unacceptable.

Quantity
requested: 3 mL whole blood
minimum: 1 mL whole blood

Processing

Processing

Store and transport whole blood at ambient temperature in original collection container.

Login: GSEND1-;ROOM TEMP

  • GSNDT1: MAYO
  • GSTYP1: WB
  • GTSRQ1: ;TTR Gene, Full Gene Analysis (Mayo Test TTRZ)

Sendouts:

  • Order Mayo Test: TTRZ.
  • Samples preferred to arrive within 96 hours of collection.

Stability: Ambient: 96 hours; Refrigerated: 96 hours; Frozen: Unacceptable.

Performance

LIS Dept Code
Performing Location(s)
Sendout Mayo Clinic Laboratories
800-533-1710

200 First Street Southwest
Rochester, MN 55901

Frequency
Performed: Varies. Report Available: 28-42 days.
Available STAT?
No

Billing & Coding

CPT codes
Billing Comments

CPT: 81404

LOINC