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Release Notes:
Data Element
Version 2010A1

Data Element Name: Time Last Known Well
Collected For: ,
Definition:The time at which the patient was last known to be without the signs and symptoms of the current stroke or at his or her prior baseline.
Suggested Data Collection Question:At what time was the patient last known to be well or at his or her prior baseline?
Allowable Values:

HH = Hour (00-23)
MM = Minutes (00-59)
ND = Time not documented or unknown at the time treatment decision was made

Converting clock time to military time:
With the exception of midnight and noon
- If the time is in the a.m., conversion is not required
- If the time is in the p.m., add 12 to the clock time hour
For example:
Midnight = 00:00
Noon = 12:00
11:59 p.m. = 23:59

Notes for Abstraction:If a stroke “onset time” is listed in the medical record, without reference to the circumstances preceding its detection, then it should be assumed to be the time last known well. Enter this time in the specified format. If there is a specific reference to the patient having been discovered with symptoms already present, then this “onset time” should be treated as a “time of symptom discovery” rather than a time of last known well and “ND” should be selected for the time last known well.

When a time of discovery is documented, but the symptom onset is not witnessed and no time last known well is documented, then “ND” should be selected for time last known well.

When the onset of symptoms is clearly witnessed, then the time last known well is identical to the time of symptom discovery.

If the time last known well is documented as being a specific number of hours prior to arrival (e.g., 2 hours ago) rather than a calendar time, subtract that number from the time of hospital or ED arrival and enter that time as the time last known well.

If the time last known well is noted to be a range of time prior to hospital or ED arrival (e.g., “2 – 3 hours ago”), assume the maximum time from the range (e.g., 3 hours), and subtract that number of hours from the time of arrival to compute the time last known well.

If there are multiple times of last known well documented, either because subsequent more accurate information became available or because of different levels of expertise in sorting out the actual time last known well, use the time recorded according to the following hierarchy:

  1. stroke team/neurology
  2. admitting physician
  3. emergency department physician
  4. ED nursing notes
  5. EMS
Suggested Data Sources:
  • Emergency department record
  • History and physical
  • Progress notes
  • Transfer documents.
Additional Notes:
Guidelines for Abstraction:
Inclusion Exclusion
  • None
  • None

Time Last Known Well
Specifications Manual for Joint Commission National Quality Core Measures (2010A1)
Discharges 04-01-10 (2Q10) through 09-30-10 (3Q10)