Unit 1: Prefixes, Suffixes, Symbols, Abbreviations, and TJC's Do Not Use List

Vocabulary practice flashcards covering medical prefixes, root words, suffixes, common medical symbols, clinical abbreviations, and prohibited designations from The Joint Commission (TJC) Do Not Use list and the Institute for Safe Medication Practices (ISMP).

Standalone Medical Prefixes

Prefixes that are always followed by a hyphen to indicate they attach to the beginning of a word (e.g., post-). When attached to root words, they do not require hyphens unless a vowel clash occurs (e.g., anti-inflammatory).

a-

Without, lack of, not (used before roots beginning with a consonant).

an-

Without, lack of, not (used before roots beginning with a vowel).

ad-

Toward.

brady-

Slow.

tachy-

Fast, rapid.

dys-

Bad, painful, difficult, abnormal.

endo-

Within, inner, inside.

ecto- / exo-

Outside; outward.

hyper-

Above, excessive, abnormally high.

hypo-

Below, deficient, abnormally low.

inter-

Between.

intra-

Within, inside.

oligo-

Few, scanty.

pan-

All, entire.

peri-

Around, surrounding.

poly-

Many, excessive.

retro-

Backward, behind.

angi/o

Vessel.

arthr/o

Joint.

encephal/o

Brain.

enter/o

Intestines.

hepat/o

Liver.

hyster/o

Uterus.

nephr/o / ren/o

Kidney.

oste/o / oss/o

Bone.

Standalone Medical Suffixes

Suffixes that require a leading hyphen to show they belong at the end of a root word (e.g., -plasty). Hyphens are not used to connect root words to suffixes.

-centesis

Surgical puncture to remove fluid.

-ectomy

Surgical removal, excision.

-emia

Blood condition, substance in the blood.

-itis

Inflammation.

-lysis

Destruction, breakdown, loosening.

-megaly

Enlargement.

-ostomy / -stomy

Surgically creating an opening/mouth; creating a new opening.

-otomy / -tomy

Surgical incision, cutting into; cutting, making a surgical incision.

-pexy

Surgical fixation, anchoring.

-plasty

Surgical repair or reconstruction.

-ptosis

Drooping, sagging, prolapse.

-rrhea

Discharge, flow.

-rrhexis

Rupture.

-stenosis

Abnormal narrowing, stricture.

-tripsy

Crushing.

Δ

Medical symbol denoting change.

@

At (error-prone medical symbol; write out the meaning instead).

and <

Greater than and less than (error-prone medical symbols; write out the meaning instead).

↑ and ↓

Higher, elevated, up (↑) and lower or down (↓).

c̄

With.

s̄

Without.

p̄

After.

ac

Before meals.

ad lib

As desired.

b.i.d. or BID

Twice a day.

t.i.d. or TID

Three times a day.

QID or q.i.d.

Four times a day.

NPO

Nothing by mouth (from Latin nil per os).

PRN or prn

As needed.

R/O or r/o

Rule out.

Rx

Prescription.

sig

Write or label; patient directions on an Rx.

SOAP

Subjective, objective, assessment, plan.

stat, STAT

Immediately.

WNL

Within normal limits.

The Joint Commission (TJC)

A regulatory agency that evaluates and accredits healthcare organizations throughout the United States to ensure they meet high standards for patient safety and quality of care.

The Joint Commission 'Do Not Use' List Policy

A published list of specific abbreviations, acronyms, symbols, and dose designations frequently misconstrued that lead to serious errors. Accredited organizations must include them on internal do-not-use lists, they must never appear in patient charting or written communications, and healthcare workers must question any order containing them.

U or u (TJC Do Not Use List)

Unit; prohibited because it can easily be misread as $0$ (e.g., 4U misread as $40$, risking tenfold dosing errors). Write 'unit' instead.

IU (TJC Do Not Use List)

International unit; prohibited due to risk of misinterpretation. Write 'international unit' instead.

Q.D., QD, q.d., or qd (TJC Do Not Use List)

Daily or once daily; prohibited due to risk of misreading. Write 'daily' instead.

Q.O.D., QOD, q.o.d., or qod (TJC Do Not Use List)

Every other day; prohibited because it is easily confused with QD. Write 'every other day' instead.

Trailing Zeroes After Decimals (X.0)

A prohibited designation because the decimal point can be missed, causing a tenfold dosing error (e.g., $4.0\,mg$ misread as $40\,mg$). Write $X$ instead of $X.0$ (Right: $4\,mg$, Wrong: $4.0\,mg$).

Lack of Leading Zeroes Before Decimals (.X)

A prohibited designation because the decimal point can be missed without a zero in front of it, causing a tenfold dosing error. Write $0.X$ instead of $.X$ (Right: $0.4\,mg$, Wrong: $.4\,mg$).

MS, MSO4, and MgSO4 (TJC Do Not Use List)

Prohibited abbreviations that can be confused with each other. Write 'morphine sulfate' or 'magnesium sulfate' instead.

µg (ISMP Error-Prone Abbreviation)

Symbol for microgram; write 'mcg' or 'microgram' instead.

SC, SQ, sub Q (ISMP Error-Prone Abbreviation)

Subcutaneous; write 'subcutaneous' instead.

D/C (ISMP Error-Prone Abbreviation)

Discharge or discontinue (two distinct meanings); write 'discharge' or 'discontinue' instead.

cc (ISMP Error-Prone Abbreviation)

Cubic centimeter, equivalent to $1\,mL$; write 'mL' or 'milliliter' instead.