Tissue Processing on Histopathology, Lecture notes of Medical Sciences

INTRODUCTION TO TISSUE PROCESSING

Within a laboratory, the histopathology section is responsible for handling tissue specimens that are affected

by disease and are bound to be observed and examined by the pathologist. It is crucial to handle the tissue specimens

properly or appropriately in order to ensure an accurate diagnosis of the condition of the patient. For the diagnosis to

infiltration, embedding, section cutting or microtomy, staining, mounting, and labelling.

Upon the acquisition and appropriate labelling of the specimen, it must be immersed in a proper fixative, that

could be routine or special, to undergo with the first step, which is fixation. Fixation is the process by which the cells in

the tissue are fixed in a chemical and physical state, and all the bi ochemical and proteolytic activities within the cells

are prevented, so that the cells or tissues can resist any morphological change or distortion after subsequent

treatment with various reagents. Fixation helps to maintain the architecture of the tissue specimen near to its original

state however, it is also the most critical step in the preparation of histological sections because, if the process is not

carried out under optimal conditions or if delayed, the tissue specimen will be subjected to irreversible damage.

Following fixation could either be dehydration or decalcification. In the process of dehydration, water within the tissue

is removed through the use of increasing concentrations of alcohol. This process is carried out to ensure that the

The cleared tissue will be, afterwards, impregnated with a suitable wax, such as paraffin or celloidin. After the

infiltration with wax, the tissue is rightfully oriented and placed in a mould that is embedded with molten wax to form

a solidified block that will be utilized for microtomy or sectioning. Take into consideration that in the process of

embedding, correct orientation of the tissue block is important because if it is the other way around, important tissue

components may be missed or damaged during microtomy. The sixth step which follows embedding is the section-

cutting. In this phase, a microtome that will cut the tissue block into ribbons or sections, that are thin enough to be

placed on a slide, is used. Having good techniques in this stage can help in minimizing artifacts or unnecessary

components in your slide and it will also help in providing successful microscopic examination. When the sectioned

tissue is placed on the slide, they are nearly visible under the light microscope that’s why, choosing the proper stain

Quality is the degree to which healthcare services strive to provide the accurate desired outcomes for patients

and are consistent w ith current professional knowledge. As pathology is significant to health care, deterioration in the

quality of pathologic services can compromise patient care and lead to adverse health events (Jose, 2013) that’s why,

all the procedures and activities of the histopathology section should be evaluated and monitored accurately through

the concept of quality control. Quality control checks in a histopathology laboratory will include accurate patient

identification, fixation, adequate processing, appropriate embedding techniques, microtomy, unacceptable artifacts

and inspection of controls to determine correctness of special stains and immunohistochemical methods. By following

these protocols or standards, the histologic technologist will not only be allowed to handle the process in the right

manner but he or she will also end up aiding the pathologist with the timely implementat ion of the accurate treatment

for the patient based on the correct interpretation of the laboratory result.