Laboratory tests help in timely and accurate diagnosis of various diseases. Laboratory tests are of decisive importance for the diagnosis of diseases: more than 60% of the information is provided by laboratory tests. The results of laboratory tests allow not only to identify the disease, but also to prescribe the appropriate treatment, so it is very important to carry it out accurately. Accuracy depends not only on the equipment with which the laboratory specialists work, but also on the patient. It is also very important to properly prepare for the examination.