CPT® Code 88366

In situ hybridization (FISH) is a sophisticated laboratory technique utilized to identify and localize specific nucleic acid sequences, including DNA and RNA, within fixed tissues or cells. This method provides critical temporal and spatial information regarding gene expression and genetic coding, which is essential for understanding the organization, regulation, and functional roles of genes within biological systems. The process begins with the fixation of sample cells or tissues, which preserves the target transcripts in their original locations. Following fixation, a DNA or RNA probe is introduced, which hybridizes, or binds, to the target nucleic acid sequence at an elevated temperature. This step is crucial as it ensures that the probe specifically attaches to the intended target, allowing for accurate detection. After hybridization, any unbound excess probe is washed away, leaving only the bound probes attached to the target sequences. The remaining DNA or RNA targets are then stained using spectrally distinct fluorophore labels, which facilitate visualization under fluorescent microscopy. The FISH technique is versatile, allowing for the simultaneous use of multiple probes to visualize co-locations of different targets within a single specimen. This capability is particularly valuable in various applications, including gene mutation analysis and the assessment of gene expression patterns. For coding purposes, CPT® Code 88365 is designated for the initial single probe stain per specimen, while CPT® Code 88364 is used for each additional single probe stain. CPT® Code 88366 is specifically reported when multiple probes are employed in the same staining procedure, reflecting the complexity and depth of analysis provided by this technique.