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

What is the most common temperature used for post-wash in FISH procedures?

1. 25 degrees Celsius

2. 30 degrees Celsius

3. 37 degrees Celsius

4. 42 degrees Celsius

The correct answer is: 37 degrees Celsius

In fluorescence in situ hybridization (FISH) procedures, the most common temperature used for post-wash is 37 degrees Celsius. This temperature is optimal for the incubation of slides as it helps in facilitating the hybridization and allows for the proper binding of probes to their target sequences. At this temperature, enzymatic reactions and molecular interactions are optimal, which enhances the sensitivity and specificity of the FISH assay. Using this temperature ensures that the fluorescent signals can be adequately amplified, which is critical for the detection of genetic abnormalities. In post-wash procedures, maintaining an appropriate temperature is essential for achieving the best results in hybridization efficiency without causing excessive non-specific binding of probes or loss of the target signal. Other temperatures, either lower or higher, might not provide the same level of efficiency and could lead to suboptimal results.