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Test Code LAB1409 Amyloidosis, Transthyretin-Associated Familial, Reflex, Blood

Additional Codes

Mayo Test ID
TTRX

 

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Diagnosis of adult individuals suspected of having transthyretin-associated familial amyloidosis

Testing Algorithm

If familial amyloidosis by liquid chromatography-mass spectrometry is abnormal, DNA sequencing will be performed at an additional charge.

 

For more information see Amyloidosis (Familial) Test Algorithm.

Method Name

Affinity Chromatography/Mass Spectrometry (MS)

Reporting Name

Familial Amyloidosis Reflex

Specimen Type

Whole blood


Shipping Instructions


Specimen must arrive within 4 days of collection. Specimens are stabilized upon receipt and stored until testing is performed.



Specimen Required


Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Refrigerated (preferred) 4 days
  Ambient  4 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Reference Values

An interpretive report will be provided.

Interpretation

The presence of a structural change in transthyretin (TTR) is suggestive of a gene variant that requires confirmation by DNA sequence analysis. A negative result by mass spectrometry does not rule out a TTR variant. Mass spectrometric (MS) results are falsely negative if the amino acid substitution does not produce a measurable mass shift for the transthyretin variant. Approximately 90% of the TTR variants are positive by MS (see Cautions).

 

After identification of the variant at the DNA level, predictive testing for at-risk family members can be performed by molecular analysis (FMTT / Familial Variant, Targeted Testing, Varies).

Day(s) Performed

Tuesday

Report Available

3 to 9 days

Specimen Retention Time

2 months

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

82542

81404 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TTRX Familial Amyloidosis Reflex 94864-6

 

Result ID Test Result Name Result LOINC Value
22668 Wild Type Mass 94860-4
22669 Wild Type Width at Half Height 94863-8
22670 Second Mass 94862-0
22671 Mass Difference 94861-2
22673 Abnormal result 51968-6
50944 Interpretation 69047-9
50946 Reviewed By 18771-6

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
TTRZ TTR Gene, Full Gene Analysis Yes No

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Hematopathology/Cytogenetics Test Request (T726)

-Biochemical Genetics Test Request (T798)