There are two commonly used fluorescence in situ hybridization (FISH) methodologies in clinical laboratories. The first will be referred to as the historical STANDARD FISH method, because it was derived from cytogenetics laboratories that first performed FISH. The second method will be referred to as the NEW histologic-based FISH method because it was derived from methods typically used in IHC laboratories.
For both methods, the fixation time and time to fixation should be recorded.
The procedure must be reproducible to be used efficiently in the clinical laboratory.