Is there a big difference in sensitivity between domestic and imported FISH hybridization kits, given that the price differs by a factor of two?

I suggest buying 2 boxes of the domestic product for trial operation as you mentioned, but do not switch directly from the imported product. For the first 20 cases, it is best to run the imported product in parallel as a control for each case, with particular attention to low-amplification and critical samples. During acceptance, check the hybridization rate, signal intensity, background, and whether enzymatic digestion is excessive. When purchasing, require the manufacturer to provide a COA and clinical testing data, and confirm whether there is NMPA registration or at least Class III filing. If the domestic manufacturer can provide on-site training or free quality control slides, the success rate will be much higher. At 40 cases per month, 2 boxes can only run 20 cases, so the trial operation period should preferably be kept within one month.

A twofold price difference does not mean a twofold difference in sensitivity. The core of HER2 FISH interpretation is reproducibility and consistency on cutoff-value samples. If a domestic kit omits certain purification steps for the fluorescently labeled antibody, the signal-to-noise ratio may be slightly worse on weakly amplified samples, but most routine clinical samples have sufficient signal. The risk lies in false negatives and nonspecific spots, so it is not advisable to look only at the quoted price. Compare the cost per test and the cost of redoing failed interpretations, and keep 1–2 tests of an imported product as an arbiter. When selecting a product, ask clearly whether the fluorescent dye is resistant to quenching and whether it matches the existing microscope filter set, to prevent rapid signal decay after purchase.

The differences between domestic and imported HER2 FISH probes are mainly reflected in batch-to-batch stability and fluorescence signal intensity, rather than whether they can be used at all. Our department has validated domestic probes, and the signal intensity is about 10-20% weaker than a certain imported brand, but by optimizing proteinase K digestion time and extending hybridization time by 2 hours, the interpretation is completely acceptable. In terms of background, domestic probes occasionally show small intranuclear dots, but be careful not to let the washing temperature run too low. If you want to start testing, the key is not to agonize over price, but to first run parallel validation using 3-5 FFPE cases each of known HER2-positive, negative, and low-amplification samples, checking signal intensity and nuclear integrity, and then make your decision.