Guides › Chart abbreviations for reviewers: the ones that change how a chart reads
Chart abbreviations for reviewers: the ones that change how a chart reads
Grouped for standard-of-care and IME reviews
Chart abbreviations for reviewers are the short forms that can shift what a record proves: NKDA, DNR, PRN, r/o, s/p, WNL, AMA and more. 1 misread can move an allergy, a code status, a diagnosis or a date. This page groups 38 of them and says why each matters in review.
Which chart abbreviations matter most in a review?
These 38 abbreviations, in 7 groups, cover most of what changes a chart's meaning: allergies and code status, history, complaints, diagnosis status, exam findings, orders and timing, and discharge and work status. Each table says what the abbreviation means and what to check on the page.
Why abbreviations matter in review
A chart is written fast, by people who share the shorthand. You read it months or years later, often from a printout, without the person who wrote it. The same letters can mean different things. In a study of the Unified Medical Language System, 33.1% of abbreviations of 6 characters or fewer had more than 1 meaning (Liu et al., 2001, checked 3 Nov 2026).
The Joint Commission requires accredited organizations to prohibit a short list: U, IU, QD, QOD, a trailing zero, a missing leading zero, MS, MSO4 and MgSO4 (Joint Commission, checked 3 Nov 2026). ISMP keeps a longer list of error-prone abbreviations that includes D/C (ISMP list, checked 3 Nov 2026). When one of these turns up in a chart you are reviewing, give the page a second look.
Allergies and code status
| Abbreviation | Means | Why it matters to a reviewer |
|---|---|---|
| NKDA | No known drug allergies | Check it against every allergy list in the file. NKDA on the admission note and a penicillin allergy on the MAR is a conflict to flag. |
| NKA | No known allergies | Broader than NKDA, since it covers food and latex too. Note which one the chart used, and where. |
| DNR | Do not resuscitate | Note when it was entered and by whom. Whether resuscitation was expected at the time of an event turns on it. |
| DNI | Do not intubate | Often entered apart from DNR. A patient can be DNI and still be full code for CPR, so read the order itself. |
History and baseline
| Abbreviation | Means | Why it matters to a reviewer |
|---|---|---|
| h/o | History of | A past condition, not a current one. "h/o DVT" is not a new DVT. |
| s/p | Status post | Marks a prior procedure or event. Look for the date. "s/p L4-5 fusion" with no date is a gap in an IME history. |
| PMH | Past medical history | Often copied forward. Compare the first PMH in the file with later ones to see what was added and when. |
| PSH | Past surgical history | Prior surgery on the same body part matters in an IME. Find the operative note, not just the list. |
| Hx | History | Context decides whether it means the patient's history or the history section of the note. |
Complaints and symptoms
| Abbreviation | Means | Why it matters to a reviewer |
|---|---|---|
| c/o | Complains of | What the patient reported, in or near their own words. It is not a finding. |
| CC | Chief complaint | The reason for the visit as first recorded. In an IME, compare it with later accounts of the injury. |
| HPI | History of present illness | The story behind the complaint. Look for the same text copied across visits. |
| SOB | Shortness of breath | A symptom to time. When SOB first appears, and what was done next, can matter more than any single reading. |
| CP | Chest pain | Also used for cerebral palsy. Read the context before you put it on a timeline. |
| ROS | Review of systems | Templated negatives are common. A "negative ROS" on a day the nursing notes describe pain is worth a row. |
Diagnosis status
| Abbreviation | Means | Why it matters to a reviewer |
|---|---|---|
| r/o | Rule out | The condition was being considered, not confirmed. Reading "r/o PE" as "PE" changes the timeline. |
| DDx | Differential diagnosis | The list of possibilities at that time. What was on it, and what was not, matters in a delayed-diagnosis review. |
| Dx | Diagnosis | Check whether it is a working or final diagnosis, and who made it. |
| c/w | Consistent with | A hedge, common in radiology and pathology reports. It supports a diagnosis without confirming it. |
| NOS | Not otherwise specified | A coding term. It tells you the chart lacks detail, not that the condition is mild. |
Exam findings
| Abbreviation | Means | Why it matters to a reviewer |
|---|---|---|
| WNL | Within normal limits | Often a template default. Check whether the exam was written out or only clicked through. |
| NAD | No acute distress | A general impression. Compare it with vitals and nursing notes from the same hour. |
| A&Ox3 | Alert and oriented to person, place and time | Mental status at that moment. A drop from A&Ox3 to A&Ox1 is a clinical event worth its own row. |
| PERRLA | Pupils equal, round, reactive to light and accommodation | Often part of a template. Its presence alone does not prove the exam was done. |
Orders, medications and timing
| Abbreviation | Means | Why it matters to a reviewer |
|---|---|---|
| PRN | As needed | The order allows a dose. It does not prove one was given. Check the MAR for each dose and its time. |
| STAT | Immediately | Compare the order time with the time it was carried out. The interval is the fact. |
| NPO | Nothing by mouth | Check the start and end times against meals or oral medications given. |
| QD | Every day | On the Joint Commission prohibited list. It has been misread as 4 times a day. |
| QOD | Every other day | Also prohibited. It has been misread as daily or as 4 times a day. |
| U | Units | Prohibited. A "U" can be read as a zero, so 4U can look like 40. |
| MS | Morphine sulfate | Prohibited, because it has been read as magnesium sulfate. In a history it can also mean multiple sclerosis or mitral stenosis. |
| MAR | Medication administration record | The record of what was given, by whom and when. Orders show intent; the MAR shows what happened. |
Discharge and work status
| Abbreviation | Means | Why it matters to a reviewer |
|---|---|---|
| AMA | Against medical advice | Look for the note that the risks were explained, and the patient's signature or refusal. It can change a causation analysis. |
| D/C | Discharge or discontinue | On the ISMP error-prone list. "D/C heparin" can mean either, so check the order log and the MAR. |
| LWBS | Left without being seen | The patient left before a provider saw them. Note the triage time and the time they left. |
| f/u | Follow-up | What was recommended, and by when. Whether the patient went is a separate question the records may answer. |
| RTW | Return to work | In an IME, list every RTW date and restriction with its provider and page. |
| MMI | Maximum medical improvement | A treating provider's statement, with a date. Your own MMI opinion is separate. |
How to read an abbreviation you are not sure of
- Read the full page, not the line. The section heading and the next sentence often settle it.
- Check the same author's other notes. People tend to abbreviate the same way each time.
- For anything about medication, check the orders and the MAR. They show what was given.
- If it still has 2 readings, say so in your report and give both. Do not pick 1 quietly.
How Medrecords AI handles abbreviations
Every line in a Medrecords AI chronology is cited to its source page. When a row turns on an abbreviation, open the page and read it in context before you rely on it. The software drafts and cites; you review, you revise, you sign.
See how that looks in the sample medical chronology, the handwritten note transcription sample and the IME report red flag checklist. For a longer reference, see our list of 150 medical abbreviations.
Frequently asked questions
What does r/o mean in a chart?
Rule out. The condition was being considered, not confirmed. Reading "r/o PE" as a diagnosis of PE changes the timeline of a review.
Which abbreviations does the Joint Commission prohibit?
U, IU, QD, QOD, a trailing zero, a missing leading zero, MS, MSO4 and MgSO4. Accredited organizations must keep them out of orders and medication documentation.
What does D/C mean in a medical record?
Discharge or discontinue. ISMP lists it as error-prone because both readings appear in charts. Check the order log and the medication administration record to see which one applies.
Send a chart full of shorthand to a demo and see every line of the chronology cited to its page. First case is free on us.