Pharmacy Sig Codes for the PTCE: High-Yield Abbreviations and Days Supply

Sig codes turn a prescriber's directions into the label language patients actually use, and they feed days-supply and quantity checks that appear throughout Order Entry and Processing on the PTCE. This guide covers high-yield frequency, route, and dosage-form abbreviations, Roman numerals used on prescriptions, ISMP warnings about error-prone abbreviations, complete reference tables, and worked days-supply examples. It is written for PTCE candidates who need speed and accuracy, not a dictionary of every obscure Latin phrase. Pair it with Order Entry and Processing practice, the PTCE pharmacy calculations guide, and the PTCE study guide.

What are pharmacy sig codes, and what does the PTCE expect?

"Sig" comes from the Latin signetur ("let it be labeled"). On an electronic or written prescription, the sig tells the patient how to take the medication: dose, route, frequency, and sometimes timing relative to meals.

Direct answer: you must translate common abbreviations into plain directions, catch unsafe or ambiguous abbreviations, and use the sig to calculate days supply when quantity and directions interact. The 2026 outline keeps sig codes (including Roman numerals) inside Order Entry and Processing.

Official domain scope is in the PTCE Content Outline PDF. Confirm policies on the PTCB CPhT certification page.

Which frequency codes are highest yield?

Memorize these until translation is automatic.

Related timing codes you will also see in banks: QAM (every morning), QPM (every evening), STAT (immediately), and QOD (every other day). Treat QOD as high-risk (see ISMP section below) even if you still recognize it on older items.

Pro Tip: Convert frequency to doses per day before you touch days supply. BID = 2/day, TID = 3/day, QID = 4/day, Q6H = 4/day, Q8H = 3/day, Q4H = 6/day. That conversion is the real skill.

Which route and form codes should you know cold?

Dosage-form shorthand that pairs with order entry: tab (tablet), cap (capsule), susp (suspension), sol (solution), ung / oint (ointment), supp (suppository), and amp (ampule). Know the meaning; prefer expanded wording on patient labels when policy requires it.

How do Roman numerals show up on prescriptions?

Roman numerals still appear in quantity and sometimes in directions (especially on older written Rxs or teaching examples).

Example: "ii tabs PO BID" means take 2 tablets by mouth twice daily (4 tablets per day).

Pro Tip: When a stem mixes Roman numerals with a days-supply ask, convert Roman to Arabic first, then compute doses per day, then divide quantity by daily use. Do not try to do all three steps in one mental pass.

Which abbreviations are error-prone (ISMP), and what should you do?

ISMP (Institute for Safe Medication Practices) publishes the List of Error-Prone Abbreviations, Symbols, and Dose Designations. The PTCE Patient Safety and Order Entry items expect you to recognize that some shortcuts are dangerous even if they are still seen in the wild.

High-risk examples commonly taught in technician programs:

On exam items, choose the answer that expands unsafe abbreviations or uses leading zeros correctly. In practice, follow pharmacy policy and pharmacist direction. For deeper safety stacking (tall man, barcode, storage), see LASA drugs and tall man lettering and Patient Safety and QA practice.

How does a sig feed days supply? (worked example)

Direct method:

1. Determine dose per administration from the sig.
2. Determine administrations per day.
3. Multiply to get units used per day.
4. Days supply = quantity dispensed ÷ units per day.

Example: Prescription reads: Amoxicillin 500 mg caps; Sig: i cap PO TID; Dispense #21.

• Dose each time: 1 capsule
• Frequency: TID = 3 times daily
• Daily use: 1 × 3 = 3 capsules/day
• Days supply: 21 ÷ 3 = 7 days

Second quick check: Prednisone 10 mg tabs; Sig: ii tabs PO BID × 5 days; Dispense enough for course.

• Daily use: 2 × 2 = 4 tablets/day
• Course: 5 days; quantity needed = 20 tablets
• If the pharmacy dispenses #20, days supply for that fill is 5 days

For more calculation patterns (D/H×Q, ratios, conversions), use the PTCE pharmacy calculations guide. Drill mixed order-entry items in Order Entry and Processing practice.

Complete sig abbreviation reference tables

Use these tables as a one-page cheat sheet. Learn what each abbreviation means, then build the reflex to convert it to plain English and a daily count without pausing.

Extended frequency and timing codes

Route of administration codes

Eye and ear laterality codes

Note: Many clinical settings prefer plain language ("right eye," "both ears") over Latin abbreviations for eye/ear routes to reduce errors.

Dosage form abbreviations

Pro Tip: ER, SR, XR, XL, and CD all indicate extended release, but they use different technologies and are not interchangeable even for the same drug. When filling, match the exact formulation code on the prescription.

Special instruction codes

Quantity and measurement abbreviations

How should you practice sig codes for a timed exam?

1. Drill frequency codes until BID/TID/QID/Q6H convert to daily counts instantly.
2. Try scenario item: QID sig tablets per day.
3. Translate 20 mixed sigs aloud into patient-friendly English.
4. Work 10 days-supply problems that force Roman numerals and PRN caveats.
5. Review ISMP-style traps so you do not pick the "traditional Latin" distractor when safety is the point.
6. Take a mixed Order Entry set on Try PTCB practice, then deepen with Order Entry practice.

PRN items need an indication and sometimes a maximum frequency ("q4h PRN pain"). If quantity is large and frequency is "as needed," days supply may be estimated from the maximum allowed daily dose under pharmacy policy. On exam stems, use the maximum frequency given in the sig when the question asks for days supply.

Frequently Asked Questions

What does BID vs TID vs QID mean?

BID is twice daily (2 doses/day). TID is three times daily (3 doses/day). QID is four times daily (4 doses/day). These three are among the most common days-supply drivers on technician exams.

Does QD still appear even if ISMP discourages it?

Yes. You may still see QD on older prescriptions, textbooks, and some exam distractors. Know that it means daily, and know that many safety systems prefer writing "daily" instead. On safety-focused questions, prefer the expanded, unambiguous option.

How do I calculate days supply from a sig?

Convert the sig to units used per day, then divide the dispensed quantity by that daily use. Example: 1 tablet BID with #60 dispensed ? 2 tablets/day ? 30 days supply.

What does gtt mean on an eye or ear drop sig?

Gtt means drop. A sig such as "i gtt OU BID" means instill 1 drop in each eye twice daily. Eye and ear abbreviation sets (OU/OS/OD, AU/AS/AD) are worth a dedicated flashcard pass.

Are Roman numerals required knowledge for the PTCE?

Yes. The content outline includes Roman numerals with sig codes under Order Entry and Processing. You should convert i, ii, iii, iv, v, x quickly and then continue the math.

Where can I practice these without only memorizing lists?

Use Order Entry and Processing practice for applied items, and use the calculations guide when days supply mixes with other math. Free warm-ups: Try PTCB.

How do sig codes relate to Patient Safety questions?

Unsafe abbreviations, missing leading zeros, and ambiguous frequencies are safety failures as much as order-entry failures. Cross-train with Patient Safety and QA practice so you recognize when the "correct Latin" answer is still the wrong clinical choice.

Make sig fluency automatic this week

Do not stop at reading tables. Force retrieval and math:

1. Write the frequency table from memory (QD through Q8H, plus PRN, HS, AC, PC).
2. Try scenario item: QID sig tablets per day.
3. Translate ten route/form codes without looking.
4. Solve five days-supply problems, including one with Roman numerals.
5. Complete one Order Entry set on Order Entry and Processing practice.
6. For structured weekly pacing, use the 4-week PTCE study plan; for fuller access, see Pricing or /ptcb.

Open Order Entry and Processing practice now and complete one set with full explanation review before moving on.