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HelpTest Code TRECS T-Cell Receptor Excision Circles Analysis, Blood
Additional Testing Requirements
This assay is useful for evaluating thymic output, and for longitudinal assessment of thymic function.
For comprehensive assessment of thymic function in pediatric patients and/or individuals who have received hematopoietic stem cell transplantation, order this test together with CD4RT / CD4 T-Cell Recent Thymic Emigrants, Blood.
Shipping Instructions
Specimens must be received in the laboratory on weekdays and by 4 p.m. on Friday. Collect and package specimen as close to shipping time as possible.
It is recommended that specimens arrive within 24 hours of collection.
Samples arriving over the weekend or on observed holidays may be canceled.
Necessary Information
Ordering physician's name and phone number are required.
TREC Assay Patient Information (T589) is required. Testing will proceed without the form; however, results will be held under the information is received.
Specimen Required
For serial monitoring, it is recommended to perform specimen collection at the same time of day, if possible.
Supplies: Ambient Shipping Box-Critical Specimens Only (T668)
Container/Tube: Lavender top (EDTA)
Specimen Volume:
Adults: 10 mL
Pediatrics
-Preferred volume for >1 year: 5 mL
-Preferred volume for ≤1 year old: 3 mL
Collection Instructions:
1. Do not collect specimen using a butterfly needle.
2. Send whole blood specimen in original tube. Do not aliquot.
Forms
TREC Assay Patient Information (T589) is required
Useful For
Measuring T-cell output or reconstitution (thymopoiesis) following hematopoietic cell transplantation or highly active antiretroviral therapy
Evaluating thymic function in patients with cellular or combined inborn errors of immunity (formerly primary immunodeficiencies), or receiving immunotherapy or cancer vaccines
Assessing T-cell recovery following thymus transplants for DiGeorge syndrome
Special Instructions
Method Name
Real-Time Quantitative Polymerase Chain Reaction (PCR)
Reporting Name
TREC Analysis, BSpecimen Type
Whole Blood EDTASpecimen Minimum Volume
Adults: 10 mL
Pediatrics: 1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Ambient | 48 hours | PURPLE OR PINK TOP/EDTA |
Reference Values
The appropriate age-related reference values will be provided on the report.
Interpretation
T-cell receptor excision circles (TREC) generally show an inverse correlation with age, although there can be substantial variations in TREC copies relative to T-cell count within a given age group.
Following hematopoietic stem cell transplantation (HSCT), highly active antiretroviral therapy (HAART), thymic transplants, etc, TREC typically increases from absent or very low levels (below age-matched reference range) to baseline levels or exceeds baseline levels, showing evidence of thymic rebound, which is consistent with recovery of thymic output and T-cell reconstitution.
When a patient is being monitored for thymic recovery post-transplant, it is recommended that a pre-transplant (prior to myeloablative or non-myeloablative conditioning) or a pretreatment baseline specimen is provided so that appropriate comparisons can be made between the pre- and post-transplant specimens. Since there is substantial variability between individuals in TREC copies, the best comparison is made to the patient's own baseline specimen rather than the reference range (which provides a guideline for TREC copies for age-matched healthy controls).
A consultative report will be generated for each patient.
Clinical Reference
1. Douek DC, McFarland RD, Keiser PH, et al: Changes in thymic function with age and during the treatment of HIV infection. Nature. 1998;396:690-694
2. Hazenberg MD, Verschuren MC, Hamann D, et al: T cell receptor excision circles as markers for recent thymic emigrants: basic aspects, technical approach, and guidelines for interpretation. J Mol Med. 2001;79:631-640
3. Gaballa A, Clave E, Uhlin M, Toubert A, Arruda LCM: Evaluating thymic function after human hematopoietic stem cell transplantation in the personalized medicine era. Front Immunol. 2020 Jul 31;11:1341. doi: 10.3389/fimmu.2020.01341
4. Parkman R, Weinberg K: Immunological reconstitution following hematopoietic stem cell transplantation. In: Thomas ED, Blume KG, Forman SJ, eds. Hematopoietic Cell Transplantation. 2nd ed. Blackwell Scientific; 1999:704-711
5. Weinberg K, Blazar BR, Wagner JE, et al: Factors affecting thymic function after allogeneic hematopoietic stem cell transplantation. Blood. 2001;97:1458-1466
6. Weinberg K, Annett G, Kashyap A, et al: The effect of thymic function on immunocompetence following bone marrow transplantation. Biol Blood Marrow Transplant. 1995;1:18-23
7. Auletta JJ, Lazarus HM: Immune restoration following hematopoietic stem cell transplantation: an evolving target. Bone Marrow Transplant. 2005;35:835-857
8. Borghans JA, Bredius RG, Hazenberg MD, et al: Early determinants of long-term T cell reconstitution after hematopoietic stem cell transplantation for severe combined immunodeficiency. Blood. 2006;108:763-769
9. Douek DC, Vescio RA, Betts MR, et al: Assessment of thymic output in adults after hematopoietic stem cell transplantation and prediction of T cell reconstitution. Lancet. 2000;355:1875-1881
10. Jamieson BD, Douek DC, Killian S, et al: Generation of functional thymocytes in the human adult. Immunity. 1999;10:569-575
11. Carmichael KF, Abayomi A: Analysis of diurnal variation of lymphocyte subsets in healthy subjects and its implication in HIV monitoring and treatment. 15th Intl Conference on AIDS, Bangkok, Thailand, 2004, Abstract B11052
12. Dimitrov S, Benedict C, Heutling D, et al: Cortisol and epinephrine control opposing circadian rhythms in T-cell subsets. Blood. 2009 May 21;113(21):5134-5143
13. Dimitrov S, Lange T, Nohroudi K, Born J: Number and function of circulating antigen presenting cells regulated by sleep. Sleep. 2007;30:401-411
14. Kronfol Z, Nair M, Zhang Q, et al: Circadian immune measures in healthy volunteers: relationship to hypothalamic-pituitary-adrenal axis hormones and sympathetic neurotransmitters. Psychosom Med. 1997;59:42-50
15. Malone JL, Simms TE, Gray GC, et al: Sources of variability in repeated T-helper lymphocyte counts from HIV 1-infected patients: total lymphocyte count fluctuations and diurnal cycle are important. J AIDS. 1990;3:144-151
16. Paglieroni TG, Holland PV: Circannual variation in lymphocyte subsets, revisited. Transfusion. 1994;34:512-516
Day(s) Performed
Varies
Report Available
6 to 8 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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
81479-Unlisted molecular pathology procedure
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TRECS | TREC Analysis, B | In Process |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 615825 | TREC Copies | 62320-7 |
| 615822 | CD3 T Cells | 8122-4 |
| 615823 | CD4 T Cells | 24467-3 |
| 615824 | CD8 T Cells | 14135-8 |
| 616642 | Previous Run Date | 93126-1 |
| 616646 | Previous run TREC Copies | 93126-1 |
| 616643 | Previous run CD3 T Cells | 93126-1 |
| 616644 | Previous run CD4 T Cells | 93126-1 |
| 616645 | Previous run CD8 T Cells | 93126-1 |
| 615826 | Interpretation | 69047-9 |
| 615827 | Additional Information | 48767-8 |
| 615828 | Method | 85069-3 |
| 615829 | Disclaimer | 62364-5 |
| 615830 | Released By | 18771-6 |