In vitro diagnosis refers to the products and services that obtain clinical information through the testing of blood, body fluids, tissues and other human samples outside the body for judging the function of the organism or diseases, and it is an important auxiliary means of modern laboratory medicine, which can provide most of the decision-making information needed for clinical diagnosis, and it has become an important part of the prevention, diagnosis, treatment and prognosis of human diseases. In vitro diagnosis is an important technical means in the medical field, which has a vital role in clinical treatment and disease prevention. In vitro diagnosis is complicated to categorize because it involves biology, medicine, electronics, machinery and many other scientific disciplines. When in vitro diagnosis is needed, it should be carried out in regular hospitals and under the guidance of doctors.