Common medical abbreviations for nurses

Updated October 13, 2026 by madebykamal

Nurses chart with a core set of abbreviations: timing such as bid and prn, routes such as PO and IV, units such as mg and mL, and shorthand such as NKDA, s/p and WNL. The list below groups them by use, with each meaning taken from MedlinePlus, ISMP, a nursing school glossary and other published lists. Facilities keep their own approved abbreviation lists, and where yours differs from any list here, your facility's list is the one that applies.

General information, not medical advice. How these guides are made.

Timing and frequency

These say when a dose or task is due. Several are Latin shorthand: q comes from quaque, every, and prn from pro re nata.

• ac: before meals.
• pc: after meals.
• bid: twice a day.
• tid: three times a day.
• qid: four times a day.
• q4h: every 4 hours. The number changes with the order, so q6h is every 6 hours.
• prn: as needed.
• stat: immediately.
• ATC: around the clock.
• NPO: nothing by mouth, from the Latin nil per os.

Routes of administration

• PO: by mouth (per os).
• IV: intravenous.
• IVPB: intravenous piggyback.
• IM: intramuscular.
• SL: sublingual.
• PR: per rectum.
• SUBQ: subcutaneous. ISMP recommends this form, in capitals with no spaces or periods, over SC, SQ and sub q.
• NG: nasogastric, as in an NG tube.

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Measurements and units

ISMP's list sets the case for volume: a capital L for liter, and mL (lowercase m, capital L) for milliliter, because a lowercase l can be read as the number 1.

• mg: milligram.
• mcg: microgram.
• kg: kilogram.
• mL: milliliter.
• L: liter.
• mEq: milliequivalent.
• mg/dL: milligrams per deciliter.

Vital signs and assessment

• VS: vital signs.
• TPR: temperature, pulse, respiration.
• BP: blood pressure.
• HR: heart rate.
• RR: respiratory rate. Some glossaries also use RR for recovery room.
• SpO2: oxygen saturation measured by pulse oximetry.
• I&O: intake and output.
• PERRLA: pupils equal, round, reactive to light and accommodation.
• LOC: level of consciousness. ASHA's list notes it can also mean loss of consciousness.
• ROM: range of motion. The same list also gives rupture of membranes.
• A&O x3: alert and oriented to person, place and time.
• SOB: shortness of breath.

History, charting and orders

• H&P: history and physical.
• Hx: history.
• Dx: diagnosis.
• Tx: treatment.
• Rx: prescription.
• c/o: complains of.
• s/p: status post, pointing to a previous condition.
• r/o: rule out.
• WNL: within normal limits.
• NKDA: no known drug allergies. NKA is no known allergies.
• DNR: do not resuscitate.

Diagnoses and tests you will hear in report

MedlinePlus, from the National Library of Medicine, includes these in its list of common abbreviations.

• HTN: hypertension, high blood pressure.
• CHF: congestive heart failure.
• COPD: chronic obstructive pulmonary disease.
• CVA: cerebrovascular accident, a stroke.
• MI: myocardial infarction, a heart attack.
• DVT: deep-vein thrombosis, a blood clot.
• DM: diabetes mellitus.
• UTI: urinary tract infection.
• CBC: complete blood count.
• BUN: blood urea nitrogen.
• CXR: chest x-ray.
• ECG or EKG: electrocardiogram.

Abbreviations to avoid because they cause errors

The Institute for Safe Medication Practices (ISMP) keeps a list of abbreviations, symbols and dose designations that were misread in reported medication errors, and says they should not be used in verbal, handwritten or electronic communication.

ISMP marks the items that are also on the Joint Commission's Do Not Use list, such as U and QD, and says those must be on every organization's own Do Not Use list; that list has its own guide under Related below.

Examples from the ISMP list:

• cc (cubic centimeters): mistaken as u (units). Use mL.
• µg, the micro sign for microgram: mistaken as mg. Use mcg.
• SC, SQ, sq or sub q (subcutaneous): SC read as SL (sublingual), and SQ read as "5 every". Use SUBQ or subcutaneous.
• D/C (discharge or discontinue): when D/C meant discharge on a medication list, it has been read as discontinue and medications were stopped too early. Write discharge, or discontinue or stop.
• AD, AS, AU (right ear, left ear, each ear) and OD, OS, OU (right eye, left eye, each eye): mistaken for one another. Write the words.
• o.d. or OD (once daily): mistaken as right eye. Use daily.
• IN (intranasal): mistaken as IM or IV. Use intranasal.
• TIW or BIW (3 or 2 times a week): mistaken as 3 or 2 times a day. Use 3 times weekly or 2 times weekly.
• SSI (sliding scale insulin): mistaken as Strong Solution of Iodine. Use sliding scale (insulin).

Typing them on a phone with ChartKey

ChartKey is a medical charting keyboard for iPhone and iPad. Its autocorrect knows 703 drug names and leaves abbreviations such as MRI, BUN, q4h and PERRLA as you typed them, and its safety guard underlines Joint Commission do-not-use abbreviations such as QD, U and IU as you type, flagging them without blocking. ChartKey is a typing tool, not a clinical reference, so confirm clinical content against your institution's approved sources.

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