For the past many years, the health industry has generated a large amount of data and it is rapidly growing with time. There is a need to store patient precious data efficiently and reliably. More efficient tools and techniques, practices, and research are required to make improvements and obtain maximum benefits from health care data.  Big data analytics is playing an important role in health care. It helps in physician's practices, maintaining patient records as well as hospitals in diagnosing diseases more precisely and accurately. In this paper, we have highlighted the role of big data in Electronic Health Records (EHRs). Under focus, the study provides an analysis of Big Data Technology in Healthcare discusses the importance of big data in health care, and compares it based on different parameters i.e., tools, techniques, classification, and performance. Furthermore, the challenges faced in the development and employment of big data-based technology in the field of the medical field are identified.

Index Terms- Big Data in Healthcare, Big data analytics, Big data comparison, EHRs, Quest diagnosis.