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Hematoxylin and Eosin Quality Control

We need to ensure quality of H&E sections, so when reviewing the daily H&E, we are looking for blue nuclei with chromatin and a well stained nuclear membrane. Also we are looking for 3 shades of eosin, light, medium and dark red/pink. Some of this is determined by the kind of eosin used.  If a control is questionable we should run a second control that we are sure of to ensure that the problem, is a staining problem and not a tissue problem. Over decalcified, over heated or poorly processed/fixed tissue can stain poorly even if all solutions in the H&E stain are OK. When doing H&E on frozen sections extra care must be taken if the slides are fixed in Formalin after cutting. Formalin or concentrated formaldehyde can act as a reducing agent. The best way to remedy this problem is to change the hematoxylin frequently. Frequently can be defined by the lab.  Some labs like clinical hospitals, where the volume is high, may determine a frequency based on number of slides, day or weeks.  Clinical labs are usually controlled by the pathologist, therefore whatever the pathologist wants, is what will become the norm. For smaller labs this is not the case.  Generally a smaller lab will inspect the color intensity of the hematoxylin on a weekly basis to determine the right time to change it.  As a rule of thumb, hematoxylin must be filtered before each days use.  This helps to keep the floating precipitate out, removes any extraneous cells and lets it keep longer.  The time in the 95% alcohols after eosin is where the three shades of eosin are differentiated so these times may need to be adjusted for best results.

Rat Liver H&E 20x
Rat Liver H&E 20x

reducing agent (also called a reductant or reducer) is the element or compound in an oxidation-reduction reaction that donates an electron to another species. Because the reducing agent is losing electrons, we say it has been oxidized. (

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The Future of Histology

Let me tell you about the growing field of histology. As you may not know, histology is the study of all normal plant, animal and human tissue. By knowing normal tissue, we can also see abnormal tissue. This leads us to the study of disease or pathology. I believe histology was created to help pathologists study disease. The histologist does all the manual labor, while the pathologist focuses on the microscopic evaluation of the tissue. This is the case today, most large hospitals have clinical histology. These can be great places to work if you like the fast paced environments. Depending on the setting, a histologist may be required to do other jobs like microbiology, cytology, electron microscopy, molecular or genetic testing. I have done some of these jobs myself. There are other applications for which histology is used. In some areas of the research industry, histology is utilized to quantify and qualify cellular research. Most of the medicines on the market have been tested in conjunction with histopathology analysis. Veterinarians rely on histopathology when they take tissue biopsies from their patients to determine the presence of disease. Marine pathologists at Woods Hole in MA use histology to test the ocean water for bacteria and other harmful contaminates by sampling clams living in it. The contaminates can be seen in the clams organs when processed and stained with H&E. It is their testing that determines if the ocean is safe to swim and fish in. Many colleges have their own histology lab to enable them to aid in the field of their research. Sometimes their research is at the forefront of new emerging technologies. In biomedical engineering, professors all over the world are creating new techneques to fix old health problems.
In this field of histology the need for qualified personel has tripled in the last ten years. In the next ten years I believe the need will more than quadruple. The median age for histologists right now is 55. To me this means, in ten years half of the histologists in the field will be retiring. The field will be in dire need. As it is right now, the average starting salary in major cities is +40,000. The job market is unbelievable. I can get a job in most major cities in the US within a week. The job market will increse its demand every year.
The manufactures of histology equipment has been creating machines to replace the absent histologist.
If you are interested in a histology career, contact us today. We can help you get started.



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