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Medical Abbreviations: The Complete Guide

Welcome to the most complete medical abbreviations reference on MedicalVideos.com — 5,715 entries covering 5,376 distinct abbreviations used in real clinical practice. Every entry gives you the abbreviation, its full form and a plain-English explanation of what it means, organised A–Z and by specialty, from prescription shorthand like BID and PRN to lab, cardiology, nursing and surgical terms. Whether you are a medical or nursing student, a newly qualified clinician, or a patient trying to understand your own chart, start with the search box — it matches the abbreviation and the meaning as you type.

Most looked up

PRNBIDTIDQIDPOIVNPOSOBCHFCOPDCBCICUSTATHTNUTI

Browse A–Z

A488 termsB255 termsC568 termsD289 termsE247 termsF238 termsG142 termsH259 termsI272 termsJ18 termsK47 termsL223 termsM363 termsN186 termsO138 termsP516 termsQ35 termsR241 termsS501 termsT334 termsU70 termsV152 termsW73 termsX11 termsY12 termsZ8 terms0–929 terms

Browse by specialty

Each specialty list is also a printable one-sheet handout — open a specialty and use its Print button. Every sheet carries the MedicalVideos.com address and a QR code back to the live, searchable list.

General Medical432 abbreviationsNursing668 abbreviationsPrescription & Medication Orders580 abbreviationsLaboratory779 abbreviationsCardiology407 abbreviationsRespiratory466 abbreviationsObstetrics & Gynecology438 abbreviationsNeurology906 abbreviationsRenal & Nephrology413 abbreviationsGastroenterology347 abbreviationsEndocrinology240 abbreviationsHematology & Oncology625 abbreviationsRadiology & Imaging394 abbreviationsSurgery798 abbreviationsEmergency & Critical Care708 abbreviationsVitals & Assessment93 abbreviationsMusculoskeletal474 abbreviationsPsychiatry415 abbreviationsPediatrics1179 abbreviationsInfectious Disease500 abbreviations

Error-prone abbreviations — read with care

A small number of abbreviations are famous for causing medication errors because they look alike, sound alike, or can be read two ways when handwritten. Safety organisations such as the ISMP (Institute for Safe Medication Practices) publish error-prone abbreviation lists, and many hospitals ban these terms from handwritten orders entirely. In this guide they carry a ⚠ Error-prone flag wherever they appear. The flagged terms in this list are:

  • AD — right ear
  • AS — left ear
  • AU — both ears
  • HS — at bedtime
  • IU — international unit
  • MgSO4 — magnesium sulfate
  • MS — mitral stenosis
  • MS — morphine sulfate
  • MS — multiple sclerosis
  • MSO4 — morphine sulfate
  • OD — right eye
  • OS — left eye
  • OU — both eyes
  • QD — quaque die
  • QHS — quaque hora somni
  • QOD — quaque altera die
  • SC — subcutaneous
  • SQ — subcutaneous
  • TIW — three times a week
  • U — unit

The safest habit is simple: when in doubt, write the full form — "once daily" instead of QD, "morphine sulfate" instead of MSO4 — and check any unclear abbreviation with the prescriber before acting on it.

Frequently asked questions

What does PRN mean in medical terms?

PRN stands for as needed (lowercase form) — latin pro re nata in lowercase charting. It is used in medication orders and care plans to show that something should be given only when the patient needs it, rather than at fixed times.

What does BID mean on a prescription?

BID stands for bis in die — twice a day. On a prescription or medication chart it tells the patient and the care team how often a medicine is taken during the day.

What are the most common medical abbreviations?

The abbreviations patients and students meet most often include BP (blood pressure), HR (hazard ratio), CBC (complete blood count), WBC (white blood cell), ECG (electrocardiogram), MRI (magnetic resonance imaging), CT (computed tomography), COPD (chronic obstructive pulmonary disease), CHF (congestive heart failure). You can look each of them up in the A–Z lists and specialty lists in this guide.

Why are some medical abbreviations called error-prone?

Some abbreviations look or sound almost identical to others, or can be read more than one way when handwritten — for example QD (once daily) can be mistaken for QID (four times a day), and MSO4 (morphine sulfate) for MgSO4 (magnesium sulfate). Patient-safety organisations such as the ISMP list these error-prone abbreviations, and many hospitals ban them from handwritten orders. They are flagged with a warning in this guide.

How do I use this medical abbreviations guide?

Type any abbreviation — or a word from its meaning — into the search box and the matching terms appear as you type. You can also browse the complete A–Z lists, open a specialty list (for example nursing, prescription or cardiology abbreviations), or open a specialty page and print it as a one-sheet handout.

Should I verify an abbreviation against my institution's approved list?

Yes. This guide is an educational reference: hospitals, clinics and countries differ in which abbreviations they allow, and some in this list are discouraged or banned locally because they are error-prone. Always follow your own institution's approved abbreviation list and local policy when writing or interpreting orders.

How many medical abbreviations are in this guide?

This guide lists 5,715 entries covering 5,376 distinct abbreviations across 20 specialties, including separate entries where one abbreviation has more than one common meaning — such as PT, which can mean physical therapy or prothrombin time depending on context.

Keep learning on MedicalVideos.com

Educational reference only. This guide is for learning and quick reference. Abbreviations vary between hospitals, countries and specialties, and some are discouraged because they can be misread. Always write and interpret orders using your own institution’s approved abbreviation list, and check anything unclear with the prescriber or your local policy.