The Groningen Hypertension Service (GHS) has demonstrated that provision of training for volunteers, technical assistance and the services of the General Practitioner Laboratory (a private foundation offering laboratory and diagnostic facilities) have enabled large rural and urban districts to be screened for hypertension within a short period of time at low cost. The GHS trained volunteers and paramedics, who assisted with the treatment for six months. The General Practitioner Laboratory evaluated treatment in nearly 600 hypertensive patients, leading to the institution of low-dose therapy and careful investigation of side-effects.