Abstract: The study is focused on the experimental research of the ambient light influence upon the blood perfusion measurement in the clinical conditions. The measurement reliability of the perfusion maps was performed on the base of Doppler method with using PeriScan PIM 3 device. The analysis leads to the list of standards and recommendations serving for the reliability improvement and the compactness of the blood perfusion measuring in the clinical conditions. The light conditions influence upon blood perfusion brings the optimization of diagnostic process and therapy as well. The blood perfusion influence was analyzed in the duplex scanning mode. The blood perfusion was statistically evaluated in the dependence of natural, fluorescent and operating light. Statistical evaluation consist linear regression representing prediction model of the blood perfusion in the dependence of a respective source of light. The important part of statistical analysis is 95% confidence intervals characterizing the estimated range of blood perfusion.