Good immunohistochemical staining is the basis and premise for correctly judging the staining results. Because there are many steps or links in the immunohistochemical staining process, each step or link may affect the final result of staining. Therefore, it is not very easy to do a high-quality immunohistochemical section. It is necessary for the pathologist and the pathologist to work closely together, coordinate and work together to ensure that qualified immunohistochemical sections are made. Although immunohistochemical staining can have various problems, from the results of staining, it can generally be divided into two categories: a colorless sheet (ie, no positive signal) and a "murmur" stained sheet (with a positive signal). The following is a description of "colorless film".
After the staining, no positive signals were seen in the sections. This is a common phenomenon in routine work. There are two possibilities for this phenomenon:
1. True negative results: There is no problem in the whole staining process, and the tissue or cells do not express the antigen associated with the antibody.
2, false negative results: that is, this negative result is not a true reflection.
The false negative results can be divided into two cases:
(1) The tissue or cells that are expected to be examined are not included in the section at all. In this case, either the pathologist chooses the wrong slice or the antibody is wrong, or the technician chooses the wrong wax block. Getting the right slice for dyeing is a prerequisite for getting the right results. This shows that the production of qualified immunohistochemical sections is not only a matter for technicians, but pathologists also play an indispensable role.
(2) Some problems have occurred in one or some of the dyeing processes. For example, tissue does not undergo antigen retrieval, some tissues must undergo antigen retrieval to detect antigen expression; or antibodies that can only be used in frozen tissue but not in paraffin-embedded tissues; or primary antibody failure, although antibody failure in theory It is a gradual overhaul, but occasionally it also encounters a sudden failure, the long-term use of antibodies and / or has exceeded the expiration date is the main reason. It can also be seen that a certain part of the dyeing process is missing, such as forgetting to add secondary or third antibody, or using two secondary antibodies instead of the third antibody, or reducing the hydrogen peroxide when formulating DAB. In order to avoid this simple error, there is a simple method: at the end of the incubation of the tri-antibody, the three anti-resistance on the slice is placed on a piece of white paper, and the prepared DAB is dropped on the third antibody of the white paper. , to see if brown appears. If it does, it proves that there is no error in the preparation process of the third antibody and DAB. If the DAB is dropped onto the slice without any positive signal, the problem must be before the third antibody. If the brown reaction does not appear on the paper, the problem must be in the preparation of the third antibody or DAB. This simple method can quickly help us find the possible causes of problems.
The problem of solving negative staining is very simple, that is, setting up a “positive controlâ€. If the positive control is expressed, there is no problem with the whole process of staining and all reagents. If the test piece is still negative at this time, it is a true negative, indicating that the tissue or cells do not have the corresponding antigen expression. Conversely, if the positive control is not colored, it indicates that something or some of the steps in the staining process have gone wrong or the reagents have gone wrong. You should look for the reasons one by one. There are two positive controls, one called "self-control" or "internal control", which means that there are known antigens in the tested sections, such as the presence of T and B cell antigens in normal lymph nodes, CD20 or CD3. There should be expression. The self-control is an ideal control. The control and test tissues or cells are in the same section and are under the same test conditions, and the results are more reliable and comparable. When choosing your own photo, it is best to choose the part that has both the diseased tissue and the normal tissue, which is good for comparison. The other is called "external control", and sometimes there is no known antigen in the slice tested, such as malignant melanoma suspected in the stomach specimen, which needs to be detected with HMB45 or Mart-1, in normal stomach tissue. There is no related antigen in itself. If the lesion has a positive reaction result, it can still indicate that it is dark, but if a negative result occurs, it is impossible to determine whether it contains melanoma antigen in its own tissue or a technical problem. Therefore, a known positive control should be established separately. This positive control outside the test tissue is referred to as an "external control." There are many situations in which an external control needs to be set up in actual work. If each antibody is to be selected with a different positive control, the workload will be large. In order to solve this problem, at present, there are units at home and abroad that integrate a variety of different organizations to make multi-tissue sections, "sausage", "spring rolls" slices, tissue chips, etc., and their continuous slice storage is ready for use. Can be used as a positive control. In addition, a relatively simple method is to use the iris as a positive control, because compared with other tissues and organs of the human body, the appendix contains more kinds of tissues, such as epithelium, lymphoid tissue, smooth muscle, interstitial, nerve, blood vessel, mesothelium and the like. A tail section can detect most commonly used antibodies.
Establishing a positive control is the task or responsibility of the pathologist, not the responsibility of the technician. The pathologist observed the HE section to see if there was a self-control in the section. If not, the technician should be told to use a positive control. Therefore, the role of pathologists in immunohistochemistry is not negligible. The antibody is not covered with the test tissue: when a small piece of scattered small tissue is stained, a certain tissue stain may be missed.
ATTENTION
1. When storing the oxygen bag, avoid light and heat, avoid contact with sharp objects, chemicals, and avoid squeezing
2. If the oxygen bag has stains or water stains, use a wrung rag to clean the oxygen bag
3. Please read the instructions carefully or purchase and use under the guidance of medical staff
4. Smoking or open flames are strictly prohibited when using
Oxygen bag,Oxygen Reservoir Bag,Oxygen Cylinder Bag,Oxygen Breathing Bag,Oxygen Carry Bag
Ningbo Queen Electronic Science Technology Co., Ltd , https://www.queenmeds.com