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X/Y Sex-Mismatch Transplant SRY/CEP X deletion Yp11.3 by FISH*

Test Code


Test Synonyms

SRY region, Yp11.3/Xp11.1q11.1


Bone marrow, stem cell transplant


Fluorescence in situ Hybridization (FISH)
*performed by affiliate laboratory

Turnaround Time

5-7 days

Specimen Requirements

2.0 mL (min. 1.0 mL) peripheral blood in sodium heparin preferred, EDTA accepted
1.0 mL (min. 0.5 mL) bone marrow in sodium heparin preferred, EDTA accepted
5 mm^3 fresh tissue in MPLN RPMI media
3.0 mL (min. 2.0 mL) FNA in MPLN RPMI media
10% neutral buffered formalin fixed paraffin embedded tissue

Specimen Stability
Peripheral blood and bone marrow stable at 4-25°C for 72 hours
Fresh tissue or FNA stable at 2-8°C for 72 hours

Storage & Handling

Peripheral blood and bone marrow, Ship with cool pack (refrigerated).
Fresh tissue, FNA or paraffin embedded tissue, ship in a Styrofoam container with a cool/refrigerated pack. (Do not allow cool pack to directly contact sample.)

Causes for Rejection

Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells; Improper fixative

Reference Range

In a normal male cell, the expected pattern is the one orange, one green signal pattern. In a normal female cell, the two orange single pattern is observed.


Bone marrow transplantation is an essential step in the management of a variety of hematological malignancies. Engraftment success can be assessed in sex-mismatched transplants by determining the sex chromosome constitution in hematopoietic cells from the transplant recipient. FISH is one of the most widely used procedures for evaluating engraftment success and for the early detection of graft failure. The CEP X/Y FISH test can be performed on interphase cells or metaphase spreads to determine the proportion of cell derived from the donor versus those derived from the recipient. The identification of chimerism (the presence of two distinct cell lines, one population from the donor and the other population from the recipient) is predictive of imminent relapse and thus impacts treatment decisions.

The CEP X/Y probe mixture is an FDA-cleared assay that utilizes probes specific for the centromeric regions of the X and Y chromosomes. A female pattern is determined by the detection of two orange signals, while a male pattern is identified by the presence of one orange and one green signal. A mixture of male and female cells is consistent with the presence of chimerism.

FISH can detect this in interphase and metaphase cells.

  1. Theide C. (2004). Diagnostic chimerism analysis after allogeneic stem cell transplantation: new methods and markers. Am J Pharmocogenomics. 4(3):177.
  2. Tamura S et al. (2000). Early detection of relapse and evaluation of treatment for mixed chimerism using fluorescence in situ hybridization following allogeneic hematopoietic cell transplant for hematological malignancies. Ann Hematol. 79(11):622.