The LOC medical abbreviation has two closely related meanings: loss of consciousness, as in a head injury history, and level of consciousness, as in a nurse's check of how alert someone is. The sentence around it settles which one the writer intended.
"No LOC" after a fall means the person was never knocked out. "LOC: alert and oriented" on a nursing assessment describes how awake and aware the patient is right now. The first is a yes or no event, the second is a scale. This page explains both, with sample lines from emergency and bedside notes.
At a glance
Meaning 1
Loss of consciousness, a past event (yes or no)Meaning 2
Level of consciousness, a current state on a scaleWritten as
LOC, +LOC, no LOC, (-) LOC, LOC x 2 minWhere you see it
ED and trauma notes, neuro checks, nursing assessmentsTools that pair with it
Do not confuse with
AMS (altered mental status)
Loss of consciousness: no LOC and positive LOC
In emergency, trauma and urgent care notes, LOC usually means loss of consciousness, a time when the person was not awake or responsive. It is a key question after any head bump, fall, crash or faint. The answer is written in a few short ways.
- No LOC or (-) LOC: the person did not pass out.
- +LOC or positive LOC: the person did lose consciousness.
- LOC x 1 min: knocked out for about one minute.
- Unknown LOC or unwitnessed: no one saw, and the person cannot recall.
A brief loss of consciousness after a head injury can raise concern for a concussion or other brain injury, so it often shapes decisions about imaging and observation. The absence of LOC does not rule out an injury, though, which is why the exam and symptoms matter too.
Level of consciousness on a nursing assessment
On bedside and neuro checks, LOC means level of consciousness, how awake and responsive a patient is right now. Nurses describe it with plain words, from alert, through drowsy or lethargic, to responding only to voice or pain, to unresponsive. They often add orientation, meaning awareness of self, place, date and current events.
Two common scales give a quick, shared language. AVPU checks whether the person is Alert, responds to Voice, responds to Pain, or is Unresponsive. The Glasgow Coma Scale scores eyes, speech and movement, with 15 as fully alert. A change in level of consciousness from one check to the next is something nurses report promptly.
Reading the LOC medical abbreviation in real notes
| Line | Meaning |
|---|---|
| "Slipped on ice, hit head, no LOC" | Did not pass out |
| "Syncopal episode with brief LOC" | Fainted and briefly lost consciousness |
| "LOC: alert, A&O x4" | Fully awake and oriented |
| "Decreased LOC, GCS 11" | Below normal alertness, scored with the coma scale |
Nurse handoff: "Post op day 1, LOC unchanged, alert and oriented, pupils equal and reactive." Here LOC means the level of alertness, and unchanged means it matches the last check.
Pupil checks are often charted with PERRLA in the same neuro section.
LOC nursing abbreviation in neuro checks
Nursing students learn to chart LOC at the start of every neuro assessment, because it is the most sensitive early sign of change in the brain. A good entry names the level in words, gives a scale score if the unit uses one, and notes orientation. Comparing with the previous entry is part of the job, since a drop of even a point or two can matter.
When the LOC abbreviation could be read either way in one note, many educators suggest spelling out which of the two meanings is intended. The nursing abbreviations guide lists more assessment shorthand.
Other uses and look alikes
LOC also appears in health care administration as level of care, for example when a team discusses moving a patient to a higher or lower level of care. It is unrelated to the neurologic meanings and appears in case management notes.
Do not mix LOC up with AMS, altered mental status, which describes confusion or a change in thinking while the person may still be awake. Someone can have AMS with a normal level of alertness.
LOC is described here in general terms only. If you or someone you care for had a head injury or passed out, the warning signs and next steps should come from a doctor or nurse who knows the details.
Frequently asked questions
What does no LOC mean in a medical note?
No LOC means no loss of consciousness. The person stayed awake and responsive through the event, such as a fall or crash.
What does positive LOC mean?
Positive LOC, written +LOC, means the person did lose consciousness, even briefly. Notes often add how long it lasted if anyone saw it.
Is LOC loss or level of consciousness?
It can be either. In an injury history it usually means loss of consciousness, while on a nursing assessment it usually means level of consciousness. The words around it make the meaning clear.
How do nurses check level of consciousness?
They see whether the person is alert, how they respond to voice and touch, and whether they know who and where they are. Many units also use the AVPU scale or the Glasgow Coma Scale for a score.