Test Background FISH involves the application of fluorescent DNA probes specific to genes or genetic regions of interest that highlight abnormalities involving these regions.
Conventional chromosome analysis is the gold standard for identification of the common, recurrent chromosome abnormalities in MDS. However, FISH is a useful adjuct to exclude common rearrangements in non-dividing cells and/or subtle rearrangements that could be missed by conventional analysis.
FISH probes commonly applied to MDS samples include, but are not limited to, the following:
Where possible, follow-up samples from patients with abnormal karyotypes are monitored by FISH only, unless frank relapse and/or disease progression are suspected, in which case conventional karyotyping will be performed in the first instance.
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 MDS referrals are treated as routine; 95% should be reported within 21 calendar days according to national guidelines. Please note however that the average turn around for this category in our laboratory is approximately 12 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 FISH only (ie follow-up samples from patients with FISH-detectable abnormalities). 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.