T-Cell Receptor Excision Circles

Abbrev Code:TREC   
Order Code:LAB6352Order Name:T-Cell Receptor Excision Circles
Synonyms:T Cell; Trec, B
Methodology:Real-time quantitative polymerase chain reaction (PCR)
CPT Codes: 81479 x1
Turnaround Time:Specimens are sent to reference laboratory Mon-Thur only; results are reported within 5-7 days
Special Instructions:

This assay is useful for longitudinal assessment of thymic function and naive T-cell production. For comprehensive thymic function analysis on pediatric patients or post-hematopoietic cell transplantation, order this test and CD4RT/CD4 T-cell Recent Thymic Emigrants (RTE).

·          Send specimen Monday through Thursday only.  Specimen should arrive within 48 hours of draw. Draw and package specimen under strict ambient conditions as close to shipping time as possible.

·          Do not draw specimen through a butterfly needle

·          Send specimen in original tube

·          Ordering physician's name and phone number are required.

·          For serial monitoring, we recommend that specimen draws be performed at the same time of day.


A completed TREC Assay Patient Information form must accompany each specimen. See Associated Links.



This test was developed and its performance characteristics determined by Laboratory Medicine and Pathology, Mayo Clinic. This test has not been cleared by the U.S. Food and Drug Administration.

Associated Links:

TREC Assay Patient Information Form

Collection Instructions

Specimen:Whole blood. Do not collect with a butterfly needle.
Optimal Volume:10 mL
Minimum\Peds Volume:Pediatric patients only: 5 mL for patients 1 year old and older. 1 mL for patients less than 1 year.
Container:Purple (EDTA)
Causes for Rejection:Gross hemolysis or lipemia.

Processing and Shipping

Specimen Processing:Whole blood. Do not aliquot,
Shipping Instructions:Ship original container at room temperature to arrive within 48 hours of collection.Protect from temperature extremes.
Stability:Stability: 48 hours at room temperature.
Test Performed at or Referral Lab Lab Sendouts  (Mayo Medical Laboratories)
Referral Lab number:TREC


Reference Range:The appropriate age-related reference values will be provided on the report.
Use:Measuring T-cell output or reconstitution (thymopoiesis) following hematopoietic cell transplantation or highly active antiretroviral therapy.

Click HERE to Report test errors or omissions.
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