Many patients who have undergone gastroscopy have had the experience that after the gastroscopy, the nurse gives you a small test tube with a very shallow bit of liquid, which is soaked with a piece of mucous membrane clamped out of your stomach, plus a Request for Pathology Examination form, and asks you to send it to the pathology department. Such patients often do not get the diagnosis immediately and need to wait a day or two before they can be given along with the pathology diagnosis report. This work we call biopsy, not only the gastroenterology department that does gastroscopy, but also the ear, nose and throat department, respiratory department, dermatology, obstetrics and gynecology, …… almost all hospital departments use biopsy when diagnosing diseases. Biopsies and pathological diagnoses, although also misdiagnosed, have a much higher accuracy and status compared to other blood tests and imaging examinations. The former yields a diagnosis that is at best a clinical diagnosis, while only the latter can be considered a definitive diagnosis. So why do biopsies and pathologies need to be done? And why do they have such a high status? It starts with the medical approach to disease diagnosis. In the most basic diagnosis, there are two elements: one is localization, from which part of the body does the disease originate? The first is qualitative, what kind of disease is it? Through the patient’s symptoms, the physician’s examination and ancillary tests, a localized diagnosis can be made, and a preliminary qualitative diagnosis can be made. Why is this qualitative diagnosis preliminary? Because it has a great deal of uncertainty. For example, based on the patient’s recent unclean diet and vomiting and diarrhea, it can be generally determined that the patient has acute gastroenteritis, but this acute gastroenteritis may be viral or bacterial, or it may even be the first attack of chronic inflammation. Another example is that while a typical liver cancer appears as a mass on CT, a rare type of liver cancer is a small nodule that diffuses throughout the liver everywhere. Because the diagnosis is ultimately made by a medical professional, the best diagnostic evidence comes from what the professional sees with his or her own eyes. However, for the safety and benefit of the patient, the lesions are generally not visible to the naked eye except for superficial injuries. Moreover, although the naked eye alone is much more accurate than CT and MRI, it still cannot make a definitive diagnosis. For example, if cancer is to be removed or treated with radiotherapy, the pathological diagnosis must be obtained under the microscope. The pathological diagnosis is not a matter of finding a random lesion and putting it under the microscope, but of cutting the human tissue into very small slices, so thin that the light can penetrate. Since this is the case, biopsy is an optimal choice: it is not necessary to get the whole lesion outside the body, but it is also able to meet the needs of pathological diagnosis. Only a small piece is needed to understand the nature of the lesion. Biopsies have become increasingly safe due to the invention of various lumpectomy and biopsy tools. Since most of the areas to be biopsied are located in the internal organs, which do not feel cuts and such, there is no additional pain associated with biopsy, except for the sensation of the lumpectomy entering the body, or the puncture needle passing through the skin. The biopsy tissue is at most a few millimeters in size and will not affect the function of the organ. Epithelial tissues like the gastric mucosa can be completely regenerated within a few days and the effect is even negligible. But the disease is also very cunning, once the biopsy leaves the body, it will be like a captured agent to start the suicide mechanism, and even ruthless: cells without oxygen supply soon die, after death, even the whole body does not remain, the release of autolysis enzymes inside the entire cell melting; protein denaturation after the entire tissue also becomes completely unrecognizable. So after the biopsy is taken out, it should be hurriedly thrown into formalin, the liquid in the small test tube at the beginning, in order to let the tissue and cell form coagulate. After being sent to the pathology department, the biopsy tissue is then dehydrated, fixed, and sectioned. Because human tissue is colorless and transparent, after slicing it into thin sections, nothing can be seen, so it also needs to be stained, so that the colorless or gray tissue shows a dark or light red-blue, the human body can be seen in the magnified world. The histological picture of the normal human body is a diverse and beautiful world, even a digestive tract, the scenery of each part is different, from the bottom of the esophagus to the bottom of the stomach to the plain of the water, and then to the highlands and hills of the gastric sinus, and then to the layers of the small intestine, …… people who have not seen it can not imagine, do not understand the human histology and physiology of people look also It is confusing. But after understanding the structure and function of the human body, even art idiots like me are able to linger. The microscopic images of the disease are a variety of damage to the beauty of the scene, and the pathologist is to determine the nature of the disease based on the scene of these damages. Although biopsy is so important in the diagnosis of disease, compared to blood tests and non-invasive imaging, biopsy still carries some risk of trauma and complications, such as tolerance of lumpectomy, bleeding at the biopsy site, infection and implantation at the puncture site, and so on. Although the incidence is very low, it needs to be used in a balanced manner. For some sites of tumor, such as the head, liver and pancreas, etc., the clinical diagnosis is mostly accurate enough without the additional risk of biopsy. Biopsy is suitable for: first, biopsy tissue is relatively easy to obtain, such as when the patient does gastroscopy by the way; second, the diagnosis is difficult to determine, such as suspected hematologic diseases, in addition to bone marrow aspiration smear, sometimes need to do bone marrow biopsy; third, the patient’s condition allows biopsy, if the patient has a tendency to bleed, biopsy may cause more than bleeding, if cardiopulmonary insufficiency, biopsy process may aggravate If the patient has a tendency to bleed, the biopsy may cause more than bleeding, and if the heart and lung function is not adequate, the biopsy process may aggravate the disease, which is not worth the loss.