The LKW medical abbreviation stands for last known well, the most recent time a person was seen or known to be at their normal baseline before stroke symptoms began. In stroke care, this one time stamp shapes which treatments are possible.
Paramedics, emergency nurses and neurologists ask for it right away, and it is recorded at the top of stroke notes, often next to CVA or a stroke scale score. This page explains how the time is set, why it is not always the same as when symptoms were noticed, and how it links to clot treatments.
At a glance
Stands for
Last known wellAlso called
Last known normal (LKN), last seen normalUsed in
Stroke care, emergency medicine, EMSWhere you see it
Ambulance reports, ED notes, stroke alertsLinked to
Written as
LKW, LKW time, LKWT
What the LKW medical abbreviation records
LKW is a time, not a symptom. It marks the last moment someone was confirmed to be acting normally. If a person was talking and moving normally at 7 in the morning and was found with facial droop at 9, the LKW is 7, not 9. The gap between those two times counts, because the stroke could have started at any point in it.
When the patient can say exactly when symptoms began, and that moment was witnessed, LKW and symptom onset are the same. When no one saw the start, the team works backward to the last confirmed normal moment.
Why the time drives stroke treatment
Many stroke treatments work only within certain windows. Clot dissolving medicines such as alteplase or tenecteplase are usually considered within about 4.5 hours of LKW for eligible patients. Mechanical thrombectomy, which removes a clot from a large artery, may be offered up to about 24 hours from LKW in selected patients with a large vessel occlusion, based on brain imaging.
| Time since LKW | What teams often consider |
|---|---|
| Within about 4.5 hours | Clot dissolving medicine, if no reason not to |
| Up to about 24 hours | Clot removal for selected large artery blockages |
| Unknown | Imaging to estimate stroke age, case by case |
Exact windows and rules come from current guidelines and each hospital's stroke protocol.
Setting LKW in real situations
Wake-up stroke: "Pt went to bed 2300 at baseline, woke 0600 with R sided weakness. LKW 2300." Because no one saw the stroke begin, the LKW is bedtime, not the moment of waking.
EMS report: "Wife reports pt normal at breakfast 0745, found slurred speech 0810. LKW 0745, RACE 6." The family's account sets the time, and the stroke scale score goes along with it.
If symptoms appear, fully clear, then return, many protocols reset LKW to the time the person was back to normal.
Terms you will see next to LKW
| Shorthand | Meaning |
|---|---|
| CVA | Stroke |
| TIA | Mini stroke with symptoms that resolve |
| CTH | CT scan of the head |
| RACE | Prehospital stroke severity scale |
| LVO | Blockage of a large brain artery |
| tPA | Clot dissolving medicine |
Together these build the quick picture a stroke team needs within the first minutes.
What family members can do
If you are with someone who suddenly shows a lopsided face, a weak arm or slurred words, calling 911 right away is the standard public advice. Noting the time they were last normal helps the team more than almost any other detail. If you are not sure, say what you do know, such as "normal at lunch, I found her at 3".
Bringing a list of their medicines, especially blood thinners, also helps the team decide on treatment quickly.
For students and new staff
Record LKW with the date as well as the clock time, and write who gave the information. Avoid using arrival time or discovery time by mistake. Other emergency terms appear in the nursing abbreviations hub.
Stroke treatment choices rest with the emergency and stroke team caring for each patient; this summary only explains the wording.
Frequently asked questions
What does LKW mean in stroke care?
LKW means last known well, the last time the patient was confirmed to be at their normal baseline. It helps decide which stroke treatments may be offered.
Is LKW the same as symptom onset?
Only when the start of symptoms was witnessed. If no one saw it begin, LKW is the last time the person was known to be normal, which can be hours earlier.
What is the LKW for a wake-up stroke?
It is usually the time the person went to sleep or was last seen normal before sleep. The time they woke up with symptoms is not used as LKW.
Why do doctors keep asking for the last known well time?
Many stroke treatments depend on how much time has passed. An accurate LKW lets the team judge whether clot treatments are possible and which imaging to order.
What does LKN mean?
LKN means last known normal. It is another name for the same idea as LKW, preferred by certain hospitals and EMS systems.