What should a tech consider when interpreting FISH analysis results?

When interpreting FISH (Fluorescence In Situ Hybridization) analysis results, the number of signals is a critical aspect to consider because it directly relates to the presence or absence of specific genetic materials or abnormalities. FISH is utilized to detect and localize the presence or absence of specific DNA sequences on chromosomes. The results are determined by counting the fluorescent signals that correspond to the hybridized probes.

For example, in normal diploid cells, one would expect to see two signals per target gene. If there are additional signals, this might indicate gene amplification, while fewer signals could suggest a deletion. Therefore, accurately interpreting the number of signals provides vital information about genetic alterations that may be relevant for diagnosis or therapeutic decisions.

While the other options might provide additional context or information, they do not directly impact the interpretation of the FISH signals in the same fundamental way as counting the number of signals does. Observing the morphology of nuclei and evaluating staining patterns can be useful but are secondary to the direct analysis of signals from the probes, which is the primary function of FISH in cytogenetics.