ISMP List of Error-Prone Abbreviations, Symbols, and Dose Designations

cc

Intended Meaning: Cubic centimeters | Misinterpretation: Mistaken as 'u' (units) | Best Practice: Use mL

IU**

Intended Meaning: International unit(s) | Misinterpretation: Mistaken as IV (intravenous) or 10 | Best Practice: Use unit(s)

l or ml

Intended Meaning: Liter or Milliliter | Misinterpretation: Lowercase 'l' mistaken as 1 | Best Practice: Use L for liter, mL for milliliter

MM / M or M / K

Intended Meaning: Million / Thousand | Misinterpretation: 'M' mistaken as thousand or million | Best Practice: Use million or thousand

Ng or ng

Intended Meaning: Nanogram | Misinterpretation: Mistaken as mg or nasogastric | Best Practice: Use nanogram

U or u**

Intended Meaning: Unit(s) | Misinterpretation: Mistaken as 0, 4, or cc (e.g., 4u seen as 40, 44, or 4cc) | Best Practice: Use unit(s)

µg

Intended Meaning: Microgram | Misinterpretation: Mistaken as mg | Best Practice: Use mcg

AD, AS, AU

Intended Meaning: Right ear, left ear, each ear | Misinterpretation: Mistaken as OD, OS, OU (eyes) | Best Practice: Use right ear, left ear, or each ear

IN

Intended Meaning: Intranasal | Misinterpretation: Mistaken as IM or IV | Best Practice: Use intranasal

IT

Intended Meaning: Intrathecal | Misinterpretation: Mistaken as intratracheal, intratumor, intratympanic, or inhalation therapy | Best Practice: Use intrathecal

OD, OS, OU

Intended Meaning: Right eye, left eye, each eye | Misinterpretation: Mistaken as AD, AS, AU (ears) | Best Practice: Use right eye, left eye, or each eye

Per os

Intended Meaning: By mouth, orally | Misinterpretation: 'os' mistaken as left eye (OS) | Best Practice: Use PO, by mouth, or orally

SC, SQ, sq, or sub qt

Intended Meaning: Subcutaneous(ly) | Misinterpretation: SC mistaken as SL; SQ mistaken as "5 every" | Best Practice: Use SUBQ or subcutaneous(ly)

o.d. or OD

Intended Meaning: Once daily | Misinterpretation: Mistaken as right eye (OD) | Best Practice: Use daily

Q.D., QD, q.d., or qd**

Intended Meaning: Every day | Misinterpretation: Mistaken as q.i.d. (four times daily) | Best Practice: Use daily

Qhst or Qnt

Intended Meaning: Nightly at bedtime | Misinterpretation: Mistaken as qhr or qh (every hour) | Best Practice: Use QHS or qhs

Q.O.D., QOD, q.o.d., or qod**

Intended Meaning: Every other day | Misinterpretation: Mistaken as qd or qid | Best Practice: Use every other day

q1d

Intended Meaning: Daily | Misinterpretation: Mistaken as qid (four times daily) | Best Practice: Use daily

q6PM

Intended Meaning: Every evening at 6 PM | Misinterpretation: Mistaken as every 6 hours | Best Practice: Use daily at 6 PM or 6 PM daily

SSRI / SSI

Intended Meaning: Sliding scale regular insulin / Sliding scale insulin | Misinterpretation: Mistaken as selective-serotonin reuptake inhibitor or Strong Solution of Iodine | Best Practice: Use sliding scale (insulin)

TIW / BIW

Intended Meaning: 3 times a week / 2 times a week | Misinterpretation: Mistaken as 3 times a day or twice a day | Best Practice: Use 3 times weekly / 2 times weekly

UD

Intended Meaning: As directed (ut dictum) | Misinterpretation: Mistaken as unit dose | Best Practice: Use as directed

BBA / BGB

Intended Meaning: Baby boy A / Baby girl B | Misinterpretation: 'B' in BBA mistaken as twin B; 'B' at end of BGB mistaken as boy | Best Practice: Use full identifiers (e.g., Smith boy A)

D/C

Intended Meaning: Discharge or discontinue | Misinterpretation: Premature discontinuation of medications | Best Practice: Use discharge and discontinue or stop

IJ

Intended Meaning: Injection | Misinterpretation: Mistaken as IV or intrajugular | Best Practice: Use injection

OJ

Intended Meaning: Orange juice | Misinterpretation: Mistaken as OD or OS (eyes) | Best Practice: Use orange juice

APAP

Intended Meaning: Acetaminophen | Misinterpretation: Not recognized as acetaminophen | Best Practice: Use acetaminophen

AZT

Intended Meaning: Zidovudine | Misinterpretation: Mistaken as azithromycin, azathioprine, or aztreonam | Best Practice: Use zidovudine

CPZ

Intended Meaning: Compazine (prochlorperazine) | Misinterpretation: Mistaken as chlorpromazine | Best Practice: Use prochlorperazine

DTO

Intended Meaning: Deodorized tincture of opium | Misinterpretation: Mistaken as tincture of opium (Paregoric) | Best Practice: Use complete drug name

HCT vs HCTZ

Intended Meaning: Hydrocortisone vs Hydrochlorothiazide | Misinterpretation: Confused for each other | Best Practice: Use hydrocortisone and hydrochlorothiazide

MgSO4**

Intended Meaning: Magnesium sulfate | Misinterpretation: Mistaken as morphine sulfate | Best Practice: Use magnesium sulfate

MS or MSO4**

Intended Meaning: Morphine sulfate | Misinterpretation: Mistaken as magnesium sulfate | Best Practice: Use morphine sulfate

MTX

Intended Meaning: Methotrexate | Misinterpretation: Mistaken as mitoxantrone | Best Practice: Use methotrexate

NoAC

Intended Meaning: Novel/new oral anticoagulant | Misinterpretation: Mistaken as "no anticoagulant" | Best Practice: Use complete drug name

OXY / PIT

Intended Meaning: Oxytocin / Pitocin | Misinterpretation: OXY mistaken as oxycodone; PIT mistaken as Pitressin | Best Practice: Use complete drug name

PNV / PTU / T3

Intended Meaning: Prenatal vitamins / Propylthiouracil / Tylenol #3 | Misinterpretation: Mistaken as Penicillin VK, Purinethol, or liothyronine (T3) | Best Practice: Use complete drug names

TNK / TPA / TXA

Intended Meaning: TNKase / tissue plasminogen activator / tranexamic acid | Misinterpretation: Confused with one another | Best Practice: Use complete drug names

Nitro drip / IV vanc / Levo / Neo

Intended Meaning: Nitroglycerin / IV vancomycin / Levofloxacin / Phenylephrine | Misinterpretation: Mistaken as nitroprusside, Invanz, Levophed, or neostigmine | Best Practice: Use complete drug names

Lack of Leading Zero (.5 mg)**

Intended Meaning: 0.5 mg | Misinterpretation: Decimal missed, misread as 5 mg | Best Practice: Use leading zero (0.5 mg)

Trailing Zero (1.0 mg)**

Intended Meaning: 1 mg | Misinterpretation: Decimal missed, misread as 10 mg | Best Practice: Do not use trailing zeros (1 mg)

and <

Intended Meaning: Greater than / Less than | Misinterpretation: Misread as opposite; < mistaken as 4 | Best Practice: Write "more than" or "less than"

↑ and ↓

Intended Meaning: Increase / Decrease | Misinterpretation: ↑ mistaken as T, 4, or 7 | Best Practice: Write "increase" or "decrease"

gr / dr / min / oz / tsp / tbsp

Intended Meaning: Grain, Dram, Minim, Ounce, Teaspoon, Tablespoon | Misinterpretation: Confused with metric units or each other | Best Practice: Use metric system (mL, mg, mcg)