9 Medical Abbreviations and Safe Usage

Why context matters

A medical abbreviation is a shortened form of a word or phrase. Although abbreviations can save space, the same letters or symbols can have different meanings in different settings. Interpret them using the surrounding text, body system, document type, and local policy rather than guessing from the letters alone.

Common abbreviations

Common abbreviations can be interpreted using clues about the information around them:

• CBC means complete blood count; a laboratory test or blood-test result is a useful clue.

• MRI means magnetic resonance imaging; an imaging test or report is a useful clue.

• CNS means central nervous system, referring to the brain and spinal cord.

• BP means blood pressure, a vital-sign measurement.

• PT may mean physical therapy or prothrombin time. A rehabilitation plan suggests physical therapy, while a blood-test result suggests prothrombin time.

• MS may refer to morphine sulfate or magnesium sulfate in medication-related writing. The drug name and order context matter, so spell out the full name to avoid confusion.

These examples are not a universal list of approved abbreviations. A facility or health system may define which abbreviations are acceptable in particular documents. Medical dictionaries and glossaries can help explain terms, but an unfamiliar abbreviation in a patient’s record should be confirmed with a qualified clinician.

Safer medication wording

Medication-related shorthand deserves special care because an unclear abbreviation, symbol, or number can change how an order is read. The Joint Commission identifies prohibited abbreviations for medication orders and related documentation, and ISMP lists additional error-prone forms. Follow the rules that apply in your organization, and prefer clear, complete wording whenever there is a risk of confusion.

Safer practices include:

• Write unit instead of U or IU, and mL instead of cc.

• Write every day or every other day instead of QD or QOD.

• Write morphine sulfate or magnesium sulfate instead of MS or similar forms that could be mistaken for one another.

• Write less than or more than rather than relying on the corresponding symbols in medication instructions.

• For a dose below one, use a leading zero, as in 0.5 mg; do not write .5 mg.

• Do not add a trailing zero to a medication dose: write 5 mg, not 5.0 mg. A decimal point can be overlooked, making a dose appear ten times larger.

• Put a space between a number and its unit: write 10 mg, not 10mg.

Check before interpreting

When you encounter an abbreviation, ask what kind of information it appears in, which nearby words narrow down its meaning, and whether another interpretation could change care or a medication dose. For example, PT beside a therapy appointment likely means physical therapy, while PT in a coagulation test result means prothrombin time.

If the context does not make the meaning clear, or if the abbreviation concerns a medication, do not guess. Check an approved reference or ask the responsible clinician or pharmacist. In general, use context to interpret familiar terms, follow local policy, avoid error-prone medication abbreviations and symbols, and verify anything unclear.