BAR means bright, alert and responsive; WNL means within normal limits; SID, BID and TID mean once, twice and three times a day; OD/OS/OU are right, left and both eyes; AD/AS/AU are the same for ears. Those cover most of what a new team member meets in week one — the full glossary below groups the rest by category, based on published university abbreviation protocols rather than folklore. One warning before the lists: several standard abbreviations have two official meanings (AS is both "left ear" and "aortic stenosis" on the same approved list), which is exactly why teaching hospitals maintain approved-abbreviation protocols at all. Rule of thumb, straight from Kansas State's official protocol: "if there is any question, the word should be written out in its entirety."
Why abbreviation discipline matters
Abbreviations exist, as Kansas State's Veterinary Health Center protocol puts it, "to save time and space." The same document draws the line that matters: "Imaginative abbreviations which mean something to only a few individuals have no place in the medical record." A note full of private shorthand fails the basic test every record must pass — that a colleague can pick it up cold and continue care safely (the standard veterinary schools teach for SOAP notes generally).
So this glossary plays it straight: the entries below come from published university lists — Kansas State's approved-abbreviations protocol and the University of Illinois veterinary library's guide (itself based on the Merck Veterinary Manual) — plus a few everyday vitals shorthands that appear in virtually every practice. Deliberately excluded: drug names and dose shorthand, which belong to your practice's own protocols and formulary, not a public glossary.
Patient status and demeanor
| Abbreviation | Meaning |
|---|---|
| BAR | Bright, alert, responsive |
| QAR | Quiet, alert, responsive |
| WNL | Within normal limits |
| NSF | No significant findings |
| NED | No evidence of disease |
| BCS | Body condition score |
| PE | Physical exam |
Two notes. First, "QAR" earns its place as the honest middle ground — a patient that's subdued but responsive is not BAR, and recording the difference matters at the next visit. Second, you'll hear ADR ("ain't doing right") in every clinic corridor; it's useful slang for an undefined malaise, but it's conspicuously absent from approved-abbreviation lists — in the record, describe what you actually observed instead.
Vitals and quick exam shorthand
| Abbreviation | Meaning |
|---|---|
| TPR | Temperature, pulse, respiration |
| HR / RR* | Heart rate / respiratory rate |
| MM* | Mucous membranes |
| CRT | Capillary refill time |
| BP | Blood pressure |
| PLR | Pupillary light response |
| PCV | Packed cell volume |
| HCT | Hematocrit |
*Asterisks are foreshadowing — see the double-meanings section below before you assume RR and MM are unambiguous.
Frequency, routes and instructions
The workhorses of every plan section:
| Abbreviation | Meaning |
|---|---|
| SID / QD | Once a day (every 24 hours) |
| BID | Twice a day |
| TID | Three times a day |
| QID | Four times a day |
| qod | Every other day |
| q | Every (q8h = every 8 hours) |
| PRN | As needed |
| PO | Per os — by mouth |
| NPO | Nothing per os — nothing by mouth |
| IV / IM / SC (SQ) | Intravenous / intramuscular / subcutaneous |
Worth knowing: SID is a veterinary invention — human medicine uses QD. If your note travels to a human pharmacist (or your practice software was built for human health care), SID is the one most likely to draw a blank stare. When in doubt, "once daily" is four keystrokes longer and cannot be misread.
Eyes and ears (the Latin quartet)
| Abbreviation | Meaning |
|---|---|
| OD | Right eye (oculus dexter) |
| OS | Left eye (oculus sinister) |
| OU | Both eyes |
| AD | Right ear (auris dextra) |
| AS | Left ear (auris sinistra) |
| AU | Both ears |
Consistent, elegant, and the source of the single best ambiguity trap in the whole glossary — see below.
History and clinical reasoning
| Abbreviation | Meaning |
|---|---|
| Hx / H/O | History / history of |
| C/S | Culture and sensitivity |
| V/D | Vomiting and diarrhea |
| PU/PD | Polyuria/polydipsia |
| HBC | Hit by car |
| FB | Foreign body |
| DDx | Differential diagnosis |
| R/O | Rule out |
| Dx / Px / Tx / Rx | Diagnosis / prognosis / treatment / prescription |
| Sx / Bx / Fx | Surgery / biopsy / fracture |
| LUX | Luxation |
| Mets | Metastases |
The reasoning shorthands (DDx, R/O) are load-bearing: "R/O foreign body" in a plan documents that you considered it and intend to exclude it — a one-line example of the visible clinical reasoning that makes an assessment defensible.
Diagnostics and procedures
| Abbreviation | Meaning |
|---|---|
| CBC | Complete blood count |
| CHEM | Chemistry panel |
| UA | Urinalysis |
| RADS | Radiographs |
| U/S (US) | Ultrasound |
| ECG | Electrocardiogram |
| ECHO | Echocardiogram |
| CT scan / MRI | Computed tomography / magnetic resonance imaging |
| CSF | Cerebrospinal fluid |
| STT | Schirmer tear test |
| PCR | Polymerase chain reaction |
| ORIF | Open reduction, internal fixation |
| THR / TPLO / FHO | Total hip replacement / tibial plateau leveling osteotomy / femoral head and neck excision |
| E-tube / PEG | Esophagostomy tube / percutaneous endoscopic gastrostomy tube |
Common conditions
A selection of the condition shorthands that appear constantly in small-animal records:
| Abbreviation | Meaning |
|---|---|
| GDV | Gastric dilatation-volvulus |
| DJD / OA | Degenerative joint disease / osteoarthrosis |
| CHF | Congestive heart failure |
| HCM / DCM | Hypertrophic / dilated cardiomyopathy |
| IVDD | Intervertebral disk disease |
| CCL / CCLR | Cranial cruciate ligament / its rupture |
| MPL / LPL | Medial / lateral patellar luxation |
| FLUTD | Feline lower urinary tract disease |
| UTI / URI | Urinary tract / upper respiratory tract infection |
| KCS | Keratoconjunctivitis sicca (dry eye) |
| OE | Otitis externa |
| IMHA | Immune-mediated hemolytic anemia |
| DKA / DM | Diabetic ketoacidosis / diabetes mellitus |
| HAC | Hyperadrenocorticism |
| FAD | Flea allergy dermatitis |
| MCT / LSA / OSA / SCC | Mast cell tumor / lymphoma / osteosarcoma / squamous cell carcinoma |
| FIP / FHV-1 | Feline infectious peritonitis / feline herpesvirus-1 |
| IBD | Inflammatory bowel disease |
| KADM | Ketoacidotic diabetes mellitus |
The trap: same letters, different meanings
This is the section to actually memorize. All of these dual meanings appear on the same official approved list — context is doing all the disambiguation work:
- AS — left ear and aortic stenosis
- TR — tricuspid regurgitation and tooth resorption
- RR — respiratory rate (everyday usage) and internal root resorption (dental charting)
- PD — periodontal disease and progressive disease (oncology)
- PT — physical therapy and prothrombin time
- MM — mucous membranes (exam shorthand) and multiple myeloma
- CT — collapsing trachea and computed tomography
- VSD — ventricular septal defect and ventral slot decompression
"AS: mild discharge" in a dermatology note and "AS" in a cardiology consult mean utterly different things. Within one section of one note, context usually saves you; across a referral, a species switch, or a locum reading cold, it can fail. The fix costs nothing: in any context where both meanings are plausible, write it out.
House rules beat any glossary
Three rules, all borrowed from the university protocols, that make abbreviations an asset instead of a risk:
- Keep one approved list per practice. Kansas State's protocol exists so that "only abbreviations on the list will be allowed to be used in the medical record" — the clinic-sized version is a one-page list in your practice wiki, and it beats every argument about what "SR" means.
- Be consistent. The same protocol again: abbreviations "should be used consistently." One clinician's OE is another's "otitis ext." — pick one form.
- When in doubt, write it out. Universal advice across every source in this article. An abbreviation saves three seconds; an ambiguous one can cost a phone call, a misread referral, or worse.
If you use an AI scribe or templates to draft your notes, the same rules apply one step earlier: configure your templates and your scribe's custom vocabulary to your practice's approved list, so the drafts arrive speaking your house style rather than teaching the team new bad habits.