Imperial Collage Healthcare

FISH analysis for Chimerism analysis (XX/XY) Post-BMT


Test Background
FISH involves the application of fluorescent DNA probes specific to genes or genetic regions of interest that highlight abnormalities involving these regions.


Clinical Indications

  • In patients who have received sex-mismatched bone marrow transplants, X/Y FISH is a useful means of rapidly screening large numbers of bone marrow cells for the presence of host cells that may be a sign of engraftment failure or early relapse.

  • Please note that this technique is different from, but complementary to, molecular chimerism analysis based on PCR of STR markers.

  • Where possible, post-BMT follow-up samples are monitored by XY FISH only, unless frank relapse is detected, in which case conventional karyotyping will also be performed, specimen type permitting.


Reference Range

N/A


Sample Required
See notes section


Sample Volume
Samples would not be rejected on the basis of small volume, however, 5 mL is ideal.


Turnaround Time
Post treatment FISH analysis is treated as routine; 95% should be reported within 21 calendar days according to national guidelines. Please note however that the average turn around for X/Y FISH in our laboratory is approximately 4 days.


Notes

Sample required:


Bone marrow in cytogenetic transport medium (preferred) or lithium heparin is usually the sample of choice. EDTA samples are only suitable in cases requiring X/Y FISH only. If in doubt please use lithium heparin. Samples which are non-sterile, clotted or collected in sodium citrate, fixative or saline are not suitable.


To ensure appropriate analysis and interpretation it is important to provide clear and concise clinical information

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