American Society for Clinical Pathology (ASCP) Technologist in Cytogenetics certification (ASCP CG) Practice Test

What is true about slide preparation for fluorescence in situ hybridization (FISH)?

1. Slides should be exposed to sunlight

2. Slides should be kept at room conditions

3. Slides must be frozen immediately

4. Slides can be stored at room temperature indefinitely

The correct answer is: Slides should be kept at room conditions

In fluorescence in situ hybridization (FISH) slide preparation, it is important to maintain the integrity of the samples to ensure accurate results. Keeping slides at room conditions is appropriate because it helps to preserve the morphology and the hybridization properties of the cellular targets. Slides prepared for FISH need to be kept at stable temperatures and humidity levels to prevent degradation of the DNA and the specificity of the fluorescent probes used in the detection. This stability is crucial to retain the quality of the hybridization signal when visualized under a fluorescence microscope. Extreme conditions, such as exposure to sunlight or freezing, can damage the cell preparations or probes. Freezing may lead to cryodamage and disrupt cellular structure, which could adversely affect hybridization efficiency. Similarly, exposure to light or inappropriate storage conditions can diminish probe viability, leading to erroneous signals in FISH analysis. Storing slides at room temperature for a reasonable duration allows for efficient hybridization without the risks associated with these more extreme conditions. Therefore, maintaining slides at room conditions is the most suitable practice for effective FISH analysis.