A human tumor wax block is required for fish testing, how thick does a white slice usually have to be cut? Can I buy only white tablets without buying wax blocks?

It is best to select batches with known fish results for quality control, especially ALK and HER2, which are markers that need to judge positive and negative patterns. You can ask the other party to provide the previous fish verification results or IHC results, indicating the amplification mode of positive cases, such as whether HER2 is clustered amplification or increased scatter, and whether alk is typically broken. This makes it easier to tell if the signal is what you expect when you get the white sheet. If the other party can only provide pathological diagnosis and no fish data, you can also buy a few tablets to pre-test yourself, but the significance of quality control will be reduced. If not, the supplier can also be asked to commit to the same origin or region as the validation batch.

Fish is generally recommended to cut 4 μm with a white tablet, because the nucleus should be in the same focal plane as possible to reduce overlap and facilitate counting. 5 μm is not completely wrong, but nuclear overlap and background signals will be slightly more, especially in areas with dense tumor cells and obvious nuclear heterotypes. Whether it is 4 or 5 μm, confirm that the other party uses a positively charged anti-removal slide, and fully bake the sheet after cutting, otherwise the fish process will change temperature repeatedly and elute easily. In addition, it is best to ask the other party to provide HE positioning or circle out the tumor area. Do not cut the white tablet randomly. If it is cut into the fibrosis or necrosis area, quality control cannot be performed.

You can only buy white tablets. Many departments also use white tablets for fish quality control, and do not necessarily need original wax blocks. However, if the supplier can cooperate to locate the tumor area, otherwise the white tablet may not be able to cut enough tumor cells. Before placing an order, ask whether the white tablets are from a known positive case, whether there is a pathological diagnosis and previous fish or IHC results, whether the biopsies are continuous, and whether the tissue area of each tablet is sufficiently counted. It is recommended to ask the other person to provide a photo of the HE or marked area adjacent to the slice, so that you can quickly find the tumor area under the microscope. Only buy white tablets. Also confirm that the transport packaging is moisture-proof and anti-shedding, and test it as soon as possible after receiving it. Do not store it at room temperature for a long time.

It is common practice to buy a few pieces of test stain first. Suppliers can generally support small packages or test pieces, but you should take the initiative. I can't give you the exact price because the price of the white tablet will be affected by the sample type, whether it has fish verification results, the completeness of the pathological data, whether it is cut 4 μm, packaging and transportation conditions. When negotiating the price, don't just ask how much each sheet costs, ask whether there is a service fee for small packages, whether HE positioning is included, and whether the failure is a patch. For the first time, it is recommended to take 3-5 tablets in the same case, and use the unified fish process to test the staining to see the signal strength, background, and tumor cell number. Tried and prepared in batches, more secure than buying a lot at once.