FIELD: medical engineering. SUBSTANCE: method involves applying measurement instrument in combination with a hollow single use unit shaped as truncated cone for measuring concentration of substance under study in biological fluid. The smaller end of the cone has porous membrane for placing biological fluid sample thereon. Reagent reacts to the substance under study with changing color in preferential cases. The measurement instrument has distal part shaped as truncated cone conjugated with the device. The measurement instrument measures color changes and calculates concentration of the substance under study in the sample. The measurement instrument and the single use device enable one to take samples in remote mode using a device minimizing probability of cross-contamination between the user and the instrument. To achieve additional protection against contamination, the devices can be mounted on and removed from the measurement instrument without touching them. EFFECT: high accuracy of measurements; high degree of contamination protection. 9 cl, 19 dwg
