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