TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

Test ID: CHIDB    
Chimerism-Donor, Varies

Useful For Suggests clinical disorders or settings where the test may be helpful

Evaluating the donor cells prior to bone marrow transplant

 

Determining the relative amounts of donor and recipient cells in a specimen.

 

An indicator of bone marrow transplant success

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Complete chimerism analysis requires 3 specimens for 3 separate tests listed below. These specimens should be submitted when collected. An interpretive report will be provided once all specimens are received.

-CHRGB / Chimerism-Recipient Germline (Pretransplant), Varies

-CHIDB / Chimerism-Donor, Varies

-CHIMU / Chimerism Transplant No Cell Sort, Varies or CHIMS / Chimerism Transplant Sorted Cells, Varies

 

Billing occurs with the following tests:

-CHRGB / Chimerism-Recipient Germline (Pretransplant), Varies; for pre-transplant and donor specimens

-CHIMU / Chimerism Transplant No Cell Sort, Varies; for unsorted post-transplant specimens

-SORT1 / Chimerism Cell Sort 1 (Bill Only) and/or SORT2 / Chimerism Cell Sort 2 (Bill Only); for sorted post-transplant specimens. ordered under CHIMS / Chimerism Transplant Sorted Cells, Varies

 

If an additional donor specimen is submitted, ADONO / Additional Chimerism Donor (Bill Only) will be performed at an additional charge.

 

See Chimerism-Recipient Germline Testing Algorithm in Special Instructions.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Patients who have had donor hematopoietic cells infused for the purpose of engraftment (ie, bone marrow transplant recipients) may have their blood or bone marrow monitored for an estimate of the percentage of donor and recipient cells present. This can be done by first identifying unique features of the donor's and the recipient's DNA prior to transplantation and then examining the recipient's blood or bone marrow after the transplantation procedure has occurred. The presence of both donor and recipient cells (chimerism) and the percentage of donor cells are indicators of transplant success.

 

Short tandem repeat (STR) sequences are used as identity markers. STRs are di-, tri-, or tetra-nucleotide repeat sequences interspersed throughout the genome at specific sites. There is variability in STR length among people and the STR lengths remain stable throughout life, making them useful as identity markers. Polymerase chain reaction is used to amplify selected STR regions from germline DNA of both donor and recipient. The lengths of the amplified fragment are evaluated for differences (informative markers). Following allogeneic hematopoietic cell infusion, the recipient blood or bone marrow can again be evaluated for the informative STR regions to identify chimerism and estimate the proportions of donor and recipient cells in the specimen.

 

This test evaluates the donor specimen prior to the recipient bone marrow transplant.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation Provides information to assist in interpretation of the test results

An interpretive report will be provided, which includes whether chimerism is detected or not and, if detected, the approximate percentage of donor and recipient cells. Sorted cell analysis permits more detailed evaluation of chimeric status in T-cell and myeloid cell fractions, which can be helpful in clinical management.

 

It is most useful to observe a trend in chimerism levels. Clinically critical results should be confirmed with 1 or more subsequent specimens.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Sensitivity varies with the proportions of donor and recipient cells in the specimen. For this reason, results are reported as approximate and rounded to the nearest 5% or 10%, depending on the calculated percentage of donor cells. For example, if the percent donor is 10% or less, it is reported as 5% donor cells. If the percent donor cells are 90% or higher, it is reported as 95% donor cells. In rare cases (eg, matched related stem cell transplants), short tandem repeat patterns may be identical (ie, noninformative) and chimeric status cannot be determined with this test. Use of alternative approaches (eg, XY fluorescence in situ hybridization in patients with opposite sex transplants) may be required.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Antin JH, Childs R, Filipovich AH, et al: Establishment of complete and mixed donor chimerism after allogenic lymphohematopoietic transplantation: recommendations from a workshop at the 2001 Tandem Meetings. Biol Blood Marrow Transplant. 2001;7:473-485

2. Tang X, Alatrash G, Ning J, et al: Increasing chimerism following allogeneic stem cell transplantation is associated with longer survivial time. Biol Blood Marrow Transplant. 2014 August;20(8):1139-1144. doi: 10.1016/j.bbmt.2014.04.003

3. Ludeman MJ, Zhong C, Mulero JJ, et al: Developmental validation of GlobalFiler PCR amplification kit: a 6-dye multiplex assay designed for amplification of casework samples. Int J Legal Med. 2018 Nov;132(6):1555-1573. doi: 10.1007/s00414-018-1817-5

4. Tyler J, Kumer L, Fisher C, et al: Personalized chimerism test that uses selection of short tandem repeat or quantitative PCR depending on patient's chimerism status. J Mol Diagn. 2019 May;21(3):483-490. doi: 10.1016/j.jmoldx.2019.01.007

5. Lion T, Watzinger F, Preuner S, et al: The EuroChimerism concept for a standardized approach to chimerism analysis after allogeneic stem cell transplantation. Leukemia. 2012 Aug;26(8):1821-1828. doi: 10.1038/leu.2012.66

Special Instructions Library of PDFs including pertinent information and forms related to the test