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6. HEME I: Introduction to Technology Ondemand
C06 HEME I Intro to Technology ADubuc
C06 HEME I Intro to Technology ADubuc
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This document provides an introduction to FISH technology and its procedural overview. FISH (Fluorescence In Situ Hybridization) is a technique used to evaluate cytogenetic aberrations below the levels of resolution of GTG banding. It allows for rapid analysis of copy number and/or structural variation without the need for cell culturing. <br /><br />The different types of FISH probes discussed include metaphase FISH and interphase FISH. Metaphase FISH assesses structural and numerical abnormalities in actively dividing cells, while interphase FISH evaluates numerical abnormalities that cannot be reliably mapped to chromosomes. Different probe types are used for enumeration, break apart, and dual-color, dual-fusion studies. <br /><br />The document also explains the nomenclature used for FISH probes, which provides information about the probe's construction, orientation, and how many probes are fused or connected. <br /><br />The process of initiating FISH testing in the lab involves obtaining and confirming the probe's localization and signal performance. Normal cutoff values are calculated based on a normal database of disease-free individuals. <br /><br />Considerations during the launch and training phase include assessing gaps in break apart probes, ensuring concordance among FISH readers, and conducting equivalency tests between old and new probe lots.<br /><br />Fixed material and truncation artifact can affect FISH results, and the size of the tissue section must be taken into account when performing FISH on fixed material.<br /><br />Lastly, the document highlights the limitations of FISH technology, such as its ability to only assess a targeted region and the potential for false negatives in the presence of complex rearrangements. However, FISH offers rapid results, can detect both numerical and structural abnormalities, and can be performed on both fresh and fixed material. It also does not require cell culture.
Keywords
FISH technology
Fluorescence In Situ Hybridization
cytogenetic aberrations
copy number
structural variation
metaphase FISH
interphase FISH
FISH probes
probe localization
fixed material
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