Embedding is an instrumental part of histotechnologists’ work, since the process of enclosing tissues or specimens so they solidify to make blocks is important for tissue orientation.
“Many tissues do require specific orientation at embedding, so that way we can see an area of interest within the specimen when we look at it under the microscope,” explained Shana Splawn, MBA, HTL (ASCP)CM, Supervisory Histotechnologist at the U.S. Department of Veterans Affairs. “Embedding is also used to provide resistance, so we can create those nice, thin sections at microtomy.”
This is possible because of the tools histologists use during embedding. In the NSH Embedding Basics and Troubleshooting webinar, Splawn describes some of these tools, and provides a look at the advantages and drawbacks of using them.
Molds. Embedding molds can come in a range of sizes and materials, and they also may be adjustable and disposable. No matter which kind histotechnologists choose, molds are important because they provide the final block shape. When choosing a mold, histologists should make sure there will be enough room for the specimen to have a border of paraffin around it. For example, while smaller molds may seem like they’re a good fit for certain samples, a ribbon may be hard to obtain when you use them.
Also, it’s important to remember to keep embedding molds clean. Even if the majority of specimens can be taken out of molds without leaving a mess behind, Splawn says there are times when this isn’t going to be the case.
“Most of the time, our specimens will come out of that mold pretty neatly and not leave anything behind,” Splawn said. “But if that tissue is under-fixed or under-processed in any way, there is a possibility that some tissue or cells may be left behind in that mold—and this can be a source of contamination.”
Tampers. Embedding tampers are small tools that can be used to push down specimens, so when they’re cut, histologists can reach all of the tissue on the same plane. Tampers are important because there should not be more wax on one side, or piece of a tissue, than another.
Unfortunately, tampers are not good for every type of specimen. Larger specimens that are a little bit warped from processing may be difficult to manage, for example.
“There are specimens that might need to be stood up on edge, or might be so brittle that just pushing them down with a tamper can cause them to break or lose their orientation,” said Splawn.
Biopsy bags. Biopsy bags are used to hold and preserve as much of a specimen as possible. They come in different materials—and no matter what kind is used in a lab, they should be handled with care.
“Make sure you open the bags carefully, especially the mesh ones. The mesh bags tend to be a little bit more rigid, so if there’s a more dense piece of tissue in there, when you go to open that bag, it can pop out,” said Splawn. “Then you’re looking for a specimen and you don’t want to do that.”
Embedding is a careful balance of technique, tools, and attention to detail. By understanding the strengths and limitations of molds, tampers, and biopsy bags—and by applying intentional tissue orientation—histotechnologists can prevent common issues before they occur. For a deeper look at these practices and more troubleshooting tips, the NSH Embedding Basics and Troubleshooting webinar offers valuable guidance for both new and experienced professionals.
#2026#Blog#GeneralAnatomicPathology