Pharmacy sig codes for the PTCB exam

Every sig code the PTCB exam expects, grouped by frequency, route, dosage form and measurement, plus the ISMP error-prone abbreviations you will be marked wrong for writing, and the prefixes, suffixes and roots behind the words.

Sig Codes and Prescription Abbreviations

Technicians must read Sig codes fluently. They appear on prescriptions, MARs, and routine communication. Misreading them is a common error pathway.

Frequency and Timing

• BID — twice daily
• TID — three times daily
• QID — four times daily
• daily — every day. Do not write q.d. — ISMP error-prone.
• q.o.d. — every other day (ISMP flags; use "every other day")
• q.a.m. / q.p.m. — every morning / every evening
• q4h, q6h, q8h, q12h — every 4, 6, 8, 12 hours
• t.i.w. — three times weekly (ISMP flags; write "3 times a week")
• HS — at bedtime (ISMP flags "HS" as ambiguous between bedtime and half-strength)
• AC — before meals
• PC — after meals
• PRN — as needed
• Stat — immediately
• hr / min — hour / minute
• NPO — nothing by mouth

Route of Administration

Eye and Ear

Dosage Form

Measurement

Other

Essential Conversion Card

Applying Sig Codes — Worked Example

"Take 1 capsule TID for 10 days."

• TID = 3 times/day.
• 1 cap × 3 × 10 = 30 capsules.

Safety Rule — Daily: Write "daily" instead of q.d. The abbreviation reads as q.i.d. too often and turns once-daily into four-times-daily dosing.

ISMP Error-Prone ("Do Not Use") Abbreviations

The Institute for Safe Medication Practices (ISMP®) publishes an Error-Prone Abbreviations list — the items below. The Joint Commission® also maintains a shorter "Official Do Not Use" list that mirrors the most dangerous entries.

For deeper coverage of error prevention, see Study Guide 3.2.

Medical Terminology

Decoding Terms from Their Component Parts

Most medical terms are built from component parts. Decoding is the skill — you do not need full anatomy.

Why Memorizing Whole Words Fails

Here's where people miss it: they try to memorize every term as a whole word instead of breaking it apart. The PTCE writes items you will not have seen before. The only reliable approach is to split the word into prefix, root, and suffix, define each piece, and reassemble the meaning.

• Word root — base component (cardi/o, hepat/o).
• Prefix — sits in front (pre-, post-, sub-).
• Suffix — attaches at the end (-itis, -ectomy, -oma).
• Combining vowel — usually "o" — links root to suffix or joins two roots.

Decoding process

1. Divide the word into components.
2. Define each component.
3. Combine into a coherent phrase.

Worked examples

• bronchoscopy = bronch/o (bronchial tube) + -scopy (visual examination) = visual inspection of the bronchi.
• electrocardiogram = electro- (electrical) + cardi/o (heart) + -gram (record) = recording of the heart's electrical activity.
• hepatitis = hepat (liver) + -itis (inflammation) = inflammation of the liver.
• nephrectomy = nephr (kidney) + -ectomy (removal) = removal of a kidney.
• cardiomegaly = cardi (heart) + -megaly (enlargement) = enlarged heart.
• pneumonia = pneum (lung) + -ia (condition) = lung condition.

High-Yield Prefixes

• a-, an- — without
• anti- — against
• brady- — slow
• dys- — difficult, painful, abnormal
• hyper- — excessive / above normal
• hypo- — deficient / below normal
• intra- — within
• olig- — few / scanty
• peri- — around
• poly- — many
• sub- — under / below
• supra- — above
• tachy- — fast

High-Yield Suffixes

High-Yield Word Roots

• cardi/o — heart
• hepat/o — liver
• nephr/o, ren/o — kidney
• pneum/o, pulmon/o — lung / air
• gastr/o — stomach
• enter/o — intestines
• neur/o — nerve
• derm/o, dermat/o — skin
• hem/o, hemat/o — blood
• cyst/o — bladder
• oste/o — bone
• arthr/o — joint
• my/o — muscle
• cephal/o — head
• thromb/o — clot
• vas/o — vessel
• ophthalm/o, ocul/o — eye
• ot/o — ear
• rhin/o — nose

Exam Tip: On medical-terminology items, the PTCE® expects decoding, not anatomy depth. Break the term into prefix + root + suffix and combine the pieces.

Safety Points

1. Fractions. Handwritten fractions are misread, especially when the slash looks like a 1. Write them clearly or convert to decimals.
2. Decimal notation. Use leading zeros on values under 1; skip trailing zeros on whole numbers. Write 0.5 mg, not .5 mg; 5 mg, not 5.0 mg.
3. Units first. Confirm the unit before calculating. Weight, volume, and strength unit mistakes propagate through the whole problem.
4. Micro symbol. The Greek µ is no longer safe — confused with m. Use mc or mcg.
5. Never abbreviate unit. U is mistaken for 0, 4, or cc. Spell it out.
6. Never use q.d. It reads as q.i.d. Write "daily" or "every day."
7. HS is ambiguous. Write "at bedtime" or "half strength" as appropriate.
8. SC/SQ are on the ISMP list. Prefer "subcut" or "subcutaneous."

Related

All Order Entry and Processing guides · What is on the PTCE and how it is weighted · The Federal Requirements domain