The Electronic Health Record (EHR) is a digital document that stores sensitive patient information. In this regard, there are novel techniques and methods for satisfying security in EHR in specific domains (such as authentication, networking, cryptography, among others). Nevertheless, there is not enough evidence on quality instruments composed of cross-cutting security metrics obtained from academic as well as grey literature. This article proposes a quality instrument that measures the satisfaction degree of security in EHRs. The instrument is composed of five security approaches and nineteen security metrics collected and characterized from the academic and grey literature. We evaluated the effectiveness of the quality instrument in a case study with 20 healthcare actors in Chile. The results suggest that the metric is quite effective, but it depends on the degree of security training of the clinical staff. The findings of this study support the idea that our quality instrument can be considered as a starting point to evaluate the quality of EHRs.