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U.S. Department of Health and Human Services

Medical Devices

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Advice for Patients: Change in Daylight Saving Time May Affect Your Medical Equipment in an Unpredictable Way

Updated:  March 8, 2013

Originally Posted:  March 1, 2007


If you have any medical equipment that uses, creates or records time information about your diagnosis or treatment and the manufacturer has not updated it, the equipment may not work properly when Daylight Saving Time (DST) starts and ends.


Beginning in 2007, the start and end dates of Daylight Saving Time in the U.S. were changed. Medical equipment you use could have been made before the DST rules were changed, and so your equipment may use the wrong dates for the start and end of daylight saving time.


If you experience a problem, it would most likely occur on the following dates:

    • March 10 (2013 start of DST)
    • April 7 (Date that DST would have started if rules hadn't changed)
    • October 27 (Date that DST would have ended if rules hadn't changed)
    • November 3 (2013 end of DST)


We do not know if any medical equipment will be affected, how it will be affected, or how it may affect patients. Although we don't know what specific equipment may fail to work correctly, we are concerned about equipment that consumers or patients use in their homes. We have already notified doctors, nurses, and hospitals of our concerns with a Public Health Notification.


What you can do

    • Check your medical equipment after 2:00 AM on March 10, 2013 to make sure it displays the correct time. If your medical equipment displays or uses the incorrect time, tell the manufacturer about your equipment and ask your doctor before you use it.
    • Check your medical equipment again after 2:00 AM on April 7, 2013 to make sure it displays the correct time. If your medical equipment displays or uses the incorrect time, tell the manufacturer about your equipment and ask your doctor before you use it.
    • Remember to check the time your equipment is displaying on October 27, 2013, and on November 3, 2013, to assure that it is correct.