Thanks to the development of the flow cytofluorimetry method, the possibilities of analyzing the immune system cells for the diagnosis of various immunopathological conditions, including HIV infection, have expanded significantly. This technology is based on the entire arsenal of modern cytochemical fluorescence methods for analyzing the structural components of cells and the processes occurring in them. One of the distinguishing features of flow cytofluorimetry is high productivity. At present, algorithms for optimizing work on these devices have been developed, recommendations have been published and an all-Russian program for quality control of laboratory studies on the section «flow cytometry» has been organized. However, the percentage of errors remains is high enough. It should also be taken into account that the immunogram indices largely depend on various factors affecting the number of peripheral blood leukocyte populations. Non-laboratory part of the preanalytical stage is very important. This is the collection of biological material in special systems, the correct selection of anticoagulant, marking of samples, as well as the storage and transportation of samples. The need to meet survey standards and assess the effectiveness of treatment for patients with HIV infection led to an increase in the number of immunological studies in the territory of the Irkutsk region. Delivery of biological material from remote areas requires the introduction of a control system, and the observance of the preanalytical stage of laboratory research. At this stage, more than half of the total number of errors that have a significant effect on the final result of the study. The application developed at the Irkutsk Regional AIDS Prevention and Control Center, measures to eliminate errors at the preanalytical stage, led to a clear reduction in the percentage of rejected samples, improved quality of laboratory tests, interpretation of the results obtained, improved diagnosis of immune system disorders and the adequacy of the antiretroviral therapy. The purpose of this work was to evaluate the effectiveness of the methodological work carried out by the specialists of the Irkutsk Regional AIDS Prevention and Control Center to improve the delivery of biological material and to reduce the percentage of rejected samples in the immunogram study. As a result of the conducted activities, there has been a tendency to reduce the number of rejected samples since the introduction of a system to improve the delivery of biological material. From all this we can draw the following conclusions. Only a set of measures aimed at improving the preanalytical stage can give a positive result, as evidenced by a reduction in the number of rejected samples from the remote areas of the Irkutsk Region to study the immune status.