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Almost all medical devices in ICU/CCU have a built-in clinical alarm system to alert when there are changes in a patient’s condition. The objective of this study is to investigate the effectiveness of the existing alarm system in ICU/CCU. Two summative usability tests were conducted to test the effectiveness of existing and new alarm signals based on IEC 60601-1-8:2006 standard. Further formative test was conducted to study perception of urgency associated with number of tones in the alarm signals. The findings indicate that the existing auditory alarm signal in ICU/CCU do not indicate the urgency of the alarm conditions. The simulation test indicates that the respondents preferred 282Hz, 500Hz and 800Hz for low, medium and high-risk alarm respectively. The one-sample proportion z test on urgency mapping indicates that the proportion of responses for highest risk is more than 50% for single tone test signal. These results show that single tone test signal being perceived as highest risk regardless of frequency. It can be concluded the auditory alarm designed based on this IEC 60608-1-8:2006 standard is not effective. As such it is proposed that incorporation of the new alarm frequencies and tones will improve the effectiveness of the alarm signal.