Chimerism Assessment by Polymorphic Microsatellite Markers

Pre-transplant Screening

Indication

- To evaluate and monitor engraftment after hematopoietic stem cell transplant using total cells (both peripheral blood and bone marrow) and ,sorted T- and myeloid cells (bone marrow only). Detection of microsatelllite markers that are exclusively donor in origin indicates successful engraftment. Serial values showing a decline in engraftment of donor cells may predict a graft-failure in appropriate clinical settings.

- To identify the source of successful engraftment when more than one donors are used from the hematopoietic stem cell transplant.

Methodology

Microsatellite-based testing for assessment of stem cell engraftment (chimerism) is performed on genomic DNA extracted from peripheral blood or bone marrow aspirate samples. For peripheral blood samples, additional testing is performed on DNA from sorted T-lymphocytes, myeloid cells and/or NK cells as applicable.

Twenty four highly informative microsatellite markers (Amelogenin, D3S1358, D8S1179, D18S51, D21S11, FGA, THO1, vWA, D5S818, D7S820, D13S317, D16S539, CSF1PO, TPOX, D1S1656, D10S1248, D12S391, D22S1045, D6S1043, Penta D, Penta E, DYS391, D2S441 and D19S433) are amplified in one multiplex-PCR reaction using fluorescently-labeled primers. PCR products are analyzed on capillary gel electrophoresis for size fractionation and quantification. The collected raw data are analyzed for the size and quantity of the peak area of the fragments using Softgenetics ChimeRMarker® Software V3.1.0

For the initial testing on any patient, the test is performed on 3 separate DNA samples: donor DNA, recipient Pre-transplant DNA, and recipient post-transplant DNA sample to identify numbers of informative markers that can distinguish between the donor and recipient. This unique set of markers will be used for subsequent Chimerism analysis on post-transplant samples only.

Final results are reported as percentage of donor DNA in total (Donor+recipient) DNA in the sample.
For clinical use, the lower limit of detection (analytical sensitivity) for this assay has been established to be at 5%.

 

Test Parameters

Peripheral blood samples are required from both donor and recipient.

Turnaround Time

Five to seven working days

Sample Requirements

  • Three 10 ml peripheral blood in purple top tube (EDTA Vacutainer), sent on wet ice

    or
  • 2-5 ml of bone marrow aspirate, sent on wet ice

CPT Codes

81265, 81267, 81268

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.