Histologic Technicians

Histologic technicians use delicate instruments, which are often computerized, to prepare tissues for microscopic scrutiny and diagnosis. They must also perform quality control tests and keep accurate records of their work.

After a tissue sample is taken, the first step in preparing it for study is known as fixation. This is usually done by a pathologist or scientist. The specimen is examined, described, trimmed to the right size, and placed in special fluids to preserve it.

When the fixed specimen arrives at the histology lab, the histologic technician removes the water and replaces it with melted wax, which moves into the tissue and provides support for the delicate cellular structure as it cools and hardens. Then the technician places small pieces of wax-soaked tissue in larger blocks of wax, a step called embedding, which prevents the tissue from collapsing during the next step of the process.

The technician then sections the specimen by mounting it on a microtome, a scientific instrument with a very sharp blade. The microtome cuts thin slices of tissue, often only one cell thick. The technician cuts many sections of tissue, usually one after another so they form a ribbon, which is placed in warm water until it flattens out. Then the prepared sections are laid on microscope slides.

Next the technician stains each tissue specimen by adding chemicals and then places a coverslip over the sample to protect it. Different stains highlight different tissue structures or abnormalities in the cells, which aids in the diagnosis and study of diseases.

A second, quicker technique is used to prepare samples and make diagnoses while the patient is still in the operating room. In these cases, tissue specimens are frozen instead of being embedded in wax. It is important for a technician to work swiftly and accurately, and cooperate with the rest of the team during this procedure because surgeries cannot be completed until test results are delivered.

Histologic technicians work with a variety of machines in the lab, such as robotic stainers, tissue processors, and cover slippers, but they must have the knowledge to perform all the functions manually should the equipment malfunction. They must also work closely with a team of researchers, as well as other laboratory and medical personnel.