FIELD: medicine. SUBSTANCE: group of inventions relates to a system for adjusting a magnetic sensor for the presence of a medicinal product in the therapy area and a method of monitoring the presence of a medicinal product in the therapy area by means of a magnetic sensor. The system contains test samples with and without magnetic substance, and a configurable sensor. Each set of test samples consists of a middle part with magnetic material enclosed between parts without any magnetic material. The magnetic material in the middle part of the sample is presented in the form of nanoparticles. The first sample in the set has the smallest sheath over the magnetic part, or no sheath at all. Each subsequent sample differs from the previous and subsequent one in terms of the diameter of the section by ΔL. Parts of samples with magnetic material are made of the same size. The sensor is configurable by installation in the device. The device is made in the form of a table with places for installing the sensor and test samples with fixing the position directly above the measuring device, with the possibility of changing the position of the test samples relative to the sensor. The method includes bringing the sensor to the place of drug delivery and taking measurements in the specified zone. The obtained data is programmatically compared with the test measurements previously obtained by the sensor tuning system. The presence of magnetic nanoparticles with the medicinal product in the required zone is determined. If magnetic nanoparticles with a medicinal product in the required zone are not detected, the process of mathematical data processing is performed by calculating the derivatives of the obtained spatial dependences of the sensor signal on its position in the specified zone in order to identify the presence of a tendency to change the sensor signal. If, during the specified procedure, magnetic nanoparticles with a medicinal product in the required area are not detected, it is concluded that the drug substance has not been delivered to the required area in the required concentration. EFFECT: fixation in the required zone at a depth from the medicinal product delivery sensor as soon as the medicinal product reaches the required zone in the patient and exceeds the “sensitivity concentration” of the affected organ to the medicinal product effect. 3 cl, 2 dwg.