The technology used in the Polygreen KP-7670, to measure blood pressure, has passed in a validation study, in a general population, according to a recognised standard protocol, as published in a peer-reviewed publication.
It is recommended by the ESH for self-measurement.
Topouchian J, Agnoletti D, Blacher J, Youssef A, Chahine MN, Ibanez I, Assemani N, Asmar R. Validation of four devices: Omron M6 Comfort, Omron HEM-7420, Withings BP-800, and Polygreen KP-7670 for home blood pressure measurement according to the European Society of Hypertension International Protocol. Vasc Health Risk Manag. 2014 Jan 16;10:33-44. doi: 10.2147/VHRM.S53968. PMID: 24476688. Available from: www.ncbi.nlm.nih.gov/pmc/articles/PMC3897354/pdf/vhrm-10-033.pdf.
ESH-IP:2010 - Pass General population