In Malaysia health-care design, developing spatial design is considered as one of the most important tasks in the preliminary design stage. In consequence, the outcome of the design gives an impact to quality of service design. The selection of quality assessment is important in support of the mission and standards of Malaysia health-care services. It is associated with a delivered a user-friendly, efficient and effective service to the patient. Hence the usability concept is attached to user’s perspective evaluation very appropriate as a measurement. The purpose of this paper is to review and understanding the” usability concept" and "Usability method" as an assessment the quality of architecture in- use”, and suggest a possible usability conceptual framework in achieving quality service design, which is an impact from that quality of architecture in-use. This paper will be focusing on three usability key factors; efficiency, effectiveness and users’ satisfaction. This overview will help researchers in their future study to investigate the relationships between the spatial design and “usability concepts". This is done by taking into considerations the user experience of the outpatient area as part of Malaysian Primary Healthcare (MPHC) service in public hospital.