--- title: "Lesson 6 — Sig Interpretation | AlabamaPharmTech.com" description: "Sig interpretation for pharmacy technicians: translate Latin abbreviations and prescription directions into accurate dispensing math." lang: en json-ld: | { "@context": "https://schema.org", "@type": "LearningResource", "name": "Sig Interpretation", "description": "Sig interpretation for pharmacy technicians: translate Latin abbreviations and prescription directions into accurate dispensing math.", "url": "https://www.alabamapharmtech.com/lessons/lesson6-sig-interpretation.html", "inLanguage": "en", "learningResourceType": "Interactive lesson", "educationalLevel": "Beginner", "isPartOf": { "@type": "Course", "name": "Pharmacy Math Mastery", "url": "https://www.alabamapharmtech.com/pharmacy-math-practice" }, "provider": { "@type": "Organization", "name": "AlabamaPharmTech", "url": "https://www.alabamapharmtech.com" } } --- AlabamaPharmTech .com An Allied Health Academy company Pharmacy Math Mastery ALBOP-Approved · PTCB & NHA Prep Overall progress 86% Lessons 1 Math Foundations 25 min · Complete ✓ 2 Dimensional Analysis 30 min · Complete ✓ 3 Day Supply Calculations 40 min · Complete ✓ 4 Dosage Conversions 35 min · Complete ✓ 5 Ratio, Proportion & Percent 35 min · Complete ✓ 6 Sig Interpretation 30 min · In progress Final exam ★ Bringing It All Together Cumulative · All 6 lessons AlabamaPharmTech.com › Pharmacy Math Mastery › Lesson 6 of 6 Core # Lesson 6: Sig Interpretation Read, translate, and calculate day supply from any prescription sig — frequency abbreviations, Roman numerals, PRN dosing rules, and complex multi-phase regimens. [Back to Course](/pharmacy-math-practice) [Back to Dashboard](/modules) Overview Examples Practice 32 Quiz The sig pipeline — read it, translate it, calculate the day supply Sig → Daily dose → Qty ÷ daily dose = day supply Every prescription you enter follows this three-step path. Reading the sig correctly is Step 1 — everything downstream depends on it. Frequency abbreviations **QD / QAM / QHS** = once daily **BID** = twice daily (every 12 hr) **TID** = three times daily **QID** = four times daily **Q4H** = every 4 hr (6×/day) **Q6H** = every 6 hr (4×/day) **Q8H** = every 8 hr (3×/day) **PRN** = as needed Route & timing **PO** = by mouth  |  **SL** = sublingual **SQ / SC** = subcutaneous **IM** = intramuscular **IV** = intravenous **AU** = both ears  |  **AD** = right ear **AS** = left ear  |  **OU** = both eyes **AC** = before meals  |  **PC** = after meals **gtt** = drops (guttae) Roman numerals in sigs ss = ½  |  i = 1  |  ii = 2  |  iii = 3 iv = 4  |  v = 5  |  vi = 6 vii = 7  |  viii = 8  |  x = 10 "Max viii tabs/day" = max 8 tablets/day "i-ii tabs" = 1 to 2 tablets Context: "iv" can be 4 OR intravenous PRN day supply rule **Always use maximum allowed frequency** for PRN medications in the day supply calculation. CII controlled substances: use the stated max dosing (not what the patient actually takes). "Q4-6H PRN" → use Q4H (6×/day) "1-2 tabs" → use 2 tablets per dose **★ PTCB tip:** Sig interpretation questions appear in Order Entry & Processing. Common test formats: (1) translate a sig to plain English, (2) calculate day supply from a sig + quantity, (3) identify the maximum daily dose from a range sig, (4) flag an early refill by comparing day supply to days since fill. Know your frequency abbreviations cold — BID vs TID vs QID is tested every exam. **Most common sig errors in practice:** (1) Entering BID as once daily — doubles refill frequency. (2) Not using max dosing for PRN CII — underestimates day supply, allows early fill. (3) Confusing "iv" (4 tablets) with "IV" (intravenous) — context is everything. (4) Missing the frequency divisor for complex tapers — 40 mg/day in 3 divided doses is NOT 40 mg per dose. Six worked examples from simple sig translation through complex multi-phase day supply calculations. Easy Retail Rx: "ii gtt AU BID." Patient asks what this means. Translate the sig to plain English. Break each abbreviation: ii = 2  |  gtt = drops  |  AU = both ears  |  BID = twice daily Plain English: Instill 2 drops in both ears twice daily. ✓ Counsel patient: 2 drops, both ears, morning and night Easy Retail Metformin 500 mg. Sig: "1 tab PO BID." Quantity: 60 tablets. Calculate the day supply. Step 1 — daily dose from sig: 1 tab × 2 (BID) = 2 tabs/day Step 2 — day supply: 60 ÷ 2 = 30 days ✓ Enter 30 days in the system Medium Retail Oxycodone 5 mg. Sig: "1-2 tabs PO Q4-6H PRN pain." Qty: 60 tabs. Schedule II. What day supply should be entered? (CII = maximum dosing) Max dose per administration: 2 tablets Max frequency: Q4H = every 4 hours = 6 times per day Max daily dose: 2 × 6 = 12 tablets/day Day supply: 60 ÷ 12 = 5 days ✓ Enter 5 days — CII always uses maximum dosing Medium Retail Albuterol HFA. Sig: "ii puffs Q4-6H PRN SOB." Canister: 200 puffs. Day supply at maximum PRN frequency (Q4H)? Max puffs per day: 2 puffs × 6 (Q4H) = 12 puffs/day Day supply: 200 ÷ 12 = 16.67 → 16 days (round down) ✓ 16-day supply — always round DOWN for day supply Hard Retail Medrol Dosepak: "6 tabs Day 1, 5 Day 2, 4 Day 3, 3 Day 4, 2 Day 5, 1 Day 6." Total tablets needed and day supply? Add each day: 6 + 5 + 4 + 3 + 2 + 1 = 21 tablets Days in course: 6 days ✓ Dispense 21 tablets, enter 6-day supply — memorize this one Hard Patient scenario TB treatment: rifampin 300 mg, "2 tabs QD × 60 days, then 1 tab QD × 120 days." Total 300 mg tablets for the complete 6-month course? Phase 1 (2 months = 60 days): 2 tabs × 60 = 120 tablets Phase 2 (4 months = 120 days): 1 tab × 120 = 120 tablets Total: 120 + 120 = 240 tablets ✓ 240 tablets total for the complete TB course **TB treatment requires a full course** — incomplete treatment causes drug-resistant TB. Dispensing the correct quantity for 6 full months is critical. Difficulty Easy Medium Hard Context Retail Hospital Patient Easy Retail Sig to English Rx label reads: "1 tab PO BID." What does this sig mean in plain English? A. 1 tablet by mouth twice dailyB. 1 tablet before meals dailyC. 1 tablet by mouth at bedtimeD. 1 tablet by mouth twice weekly Show solution **Answer: 1 tablet by mouth twice daily** **PO** = by mouth. **BID** = bis in die = twice per day. "1 tablet by mouth twice daily." Easy Retail Sig to English Rx: "1-2 tabs PO Q4-6H PRN pain." What does PRN mean? Check Show solution **Answer: As needed** **PRN** = pro re nata (Latin) = **as needed**. Patient takes the dose only when the symptom is present. Easy Retail Sig to English Rx: "1 cap PO QHS." When should the patient take this medication? A. Every morningB. Twice dailyC. At bedtimeD. With food only Show solution **Answer: At bedtime** **QHS** = quaque hora somni = every hour of sleep = **at bedtime**. Same as QD for day supply purposes. Med Retail Sig to English Rx: "1 tab PO AC." When does the patient take this medication? A. After mealsB. Before mealsC. With mealsD. Between meals Show solution **Answer: Before meals** **AC** = ante cibum = **before meals**. **PC** = post cibum = after meals. Common with antacids, metformin (PC), and some diabetes medications (AC). Med Retail Sig to English Rx: "ii gtt AU BID." What does this sig instruct the patient to do? A. 2 drops in the right ear twice dailyB. 2 drops in both ears twice dailyC. 2 drops in the left eye twice dailyD. 2 drops in each ear twice daily Show solution **Answer: 2 drops in both ears twice daily** **ii** = 2, **gtt** = drops, **AU** = both ears (auris utraque), **BID** = twice daily. "Instill 2 drops in both ears twice daily." Note: AU = both, AD = right ear, AS = left ear. Hard Retail Sig to English Full sig: "Take i-ii tabs PO Q4-6H PRN pain. Max iv tabs/day." What is the maximum number of tablets the patient may take in one day? A. 2 tabletsB. 4 tabletsC. 6 tabletsD. 8 tablets Show solution **Answer: 4 tablets** "Max iv tabs/day." **iv = 4** in Roman numerals. The patient may take a maximum of **4 tablets per day** regardless of frequency. Easy Retail Sig → Day Supply Sig: "1 tab PO QD." Quantity dispensed: 90 tablets. What day supply should be entered? Check Show solution **Answer: 90 days** 1 tab × 1 (QD) = 1 tab/day. 90 ÷ 1 = **90 days**. Easy Retail Sig → Day Supply Sig: "1 tab PO QAM." Quantity: 30 tablets. Day supply? Check Show solution **Answer: 30 days** QAM = every morning = once daily. 30 ÷ 1 = **30 days**. Easy Retail Sig → Day Supply Sig: "i tab PO BID." Quantity: 60 tablets. Day supply? Check Show solution **Answer: 30 days** i = 1. 1 × 2 (BID) = 2 tabs/day. 60 ÷ 2 = **30 days**. Med Retail Sig → Day Supply Sig: "1 cap PO TID." Quantity: 30 capsules. Day supply? Check Show solution **Answer: 10 days** 1 × 3 (TID) = 3 caps/day. 30 ÷ 3 = **10 days**. Med Retail Sig → Day Supply Oxycodone 5 mg. Sig: "1-2 tabs PO Q4-6H PRN pain." Qty: 60 tabs. Schedule II — use maximum dosing. What day supply should be entered? Check Show solution **Answer: 5 days** Max: 2 tabs × 6 (Q4H) = 12 tabs/day. 60 ÷ 12 = **5 days**. CII controlled substances always use maximum dosing for day supply. Med Retail Sig → Day Supply Ibuprofen 400 mg. Sig: "ii tabs PO Q6H PRN." Qty: 120 tabs. Day supply using max frequency? Check Show solution **Answer: 15 days** Max: 2 × 4 (Q6H) = 8 tabs/day. 120 ÷ 8 = **15 days**. Med Retail Sig → Day Supply Sig: "i tab PO QD." Qty: 30 tablets. Day supply? Check Show solution **Answer: 30 days** 1 × 1 (QD) = 1 tab/day. 30 ÷ 1 = **30 days**. Hard Retail Sig → Day Supply Sig: "1 tab PO BID × 10 days (herpes outbreak)." How many tablets are needed for the complete course? A. 10 tabletsB. 14 tabletsC. 20 tabletsD. 30 tablets Show solution **Answer: 20 tablets** 1 × 2 (BID) × 10 days = **20 tablets**. Hard Retail Sig → Day Supply Sig: "1 tab PO Q12H × 5 days, then 1 tab PO QD × 5 days." Total tablets needed? A. 10 tabletsB. 15 tabletsC. 20 tabletsD. 25 tablets Show solution **Answer: 15 tablets** Q12H × 5d: 2 × 5 = 10. QD × 5d: 1 × 5 = 5. Total: 10 + 5 = **15 tablets**. Hard Patient scenario Sig → Day Supply Albuterol HFA. Sig: "ii puffs Q4-6H PRN SOB." Canister: 200 puffs. Day supply at max frequency (Q4H = 6 times/day)? Check Show solution **Answer: 16 days** Max puffs/day: 2 × 6 = 12. 200 ÷ 12 = 16.67 → **16 days** (round down). Easy Retail Roman Numerals Rx reads: "i tab PO QD." How many tablets does the patient take per day? A. 1 tabletB. 2 tabletsC. 3 tabletsD. 4 tablets Show solution **Answer: 1 tablet** "i" in Roman numerals = **1**. In pharmacy sigs, lowercase Roman numerals are used for quantities. Easy Retail Roman Numerals Rx reads: "take ss tab PO BID." How many total tablets does the patient take per day? A. 0.5 tabletsB. 1 tabletC. 2 tabletsD. 4 tablets Show solution **Answer: 1 tablet** "ss" = semis = one-half = 0.5 tablet. BID = twice daily. 0.5 × 2 = **1 tablet per day**. Easy Retail Roman Numerals Sig states: give "iii gtt." Roman numeral "iii" equals: Check Show solution **Answer: 3** "iii" = 3. i = 1, ii = 2, iii = 3, iv = 4, v = 5, vi = 6, vii = 7, viii = 8, ix = 9, x = 10. Med Retail Roman Numerals A Rx reads: "Max iv tabs/day." What does "iv" mean in this context? A. 4 — intravenous route onlyB. 6C. 4 — can mean tablets OR intravenous route depending on contextD. Has no standard meaning in pharmacy Show solution **Answer: 4 — can mean tablets OR intravenous route depending on context** "iv" in Roman numerals = **4**. In a tablet sig, iv = 4 tablets. But "IV" (uppercase) also means intravenous. **Context determines meaning** — always read the full sig carefully. Med Retail Roman Numerals Cough syrup Rx: "iii gtt PO Q4H PRN." How many drops per dose? A. 1 dropB. 2 dropsC. 3 dropsD. 4 drops Show solution **Answer: 3 drops** "iii gtt" = **3 drops** (iii = 3, gtt = drops from guttae). Hard Retail Roman Numerals Rx: "i-ii caps PO QID PRN. Max viii caps/day." Using the stated maximum, how many capsules per day? Check Show solution **Answer: 8 capsules** "Max viii caps/day." viii = **8 capsules per day** maximum. Med Retail PRN Day Supply Zolpidem 10 mg. Sig: 1 tab QHS PRN insomnia. Qty: 30 tabs. Patient reports taking it 4 nights/week. Approximately how many weeks will 30 tablets last at 4 nights per week? Check Show solution **Answer: 7.5 weeks** 30 tabs ÷ 4 per week = **7.5 weeks**. Med Retail PRN Day Supply Alprazolam 0.25 mg. Sig: 1 tab PO TID PRN anxiety. Qty: 30 tabs. Day supply entered using maximum frequency? Check Show solution **Answer: 10 days** 1 × 3 (TID) = 3 tabs/day at max. 30 ÷ 3 = **10 days**. Med Retail PRN Day Supply Hydrocodone/APAP 5/325 mg. Sig: 1-2 tabs Q4-6H PRN. Qty: 30 tabs. Schedule II. CII day supply using maximum dosing (2 tabs × Q4H = 12/day)? Check Show solution **Answer: 2 days** Max: 2 × 6 = 12 tabs/day. 30 ÷ 12 = 2.5 → **2 days** (round down). Hard Retail PRN Day Supply Patient fills #30 Norco (calculated day supply = 2 days at max dose) on Day 1. Returns Day 3 asking for a refill. Can the patient refill on Day 3? A. No — must wait 30 days minimum for CIIB. Yes — the 2-day supply elapsed by Day 3C. No — CII requires 30-day wait from original fillD. Yes — but only a 7-day emergency supply Show solution **Answer: Yes — the 2-day supply elapsed by Day 3** Day supply = 2 days from Day 1. Refill eligible from Day 3 onward. Patient is on Day 3. **Yes — the supply has elapsed and a new Rx may be filled.** CII rules limit quantity, not necessarily the refill window on a new written Rx. Hard Retail PRN Day Supply Metoprolol 25 mg #90, 1 tab QD (scheduled). Alprazolam 0.5 mg #30, 1 tab TID PRN (max dosing for day supply). Which has the longer entered day supply, and what are the two values? Check Show solution **Answer: Metoprolol — 90 days vs alprazolam 10 days (max PRN)** Metoprolol: 90 ÷ 1 = 90 days. Alprazolam (max PRN): 30 ÷ 3 = **10 days**. PRN medications use max frequency for day supply — 10 days is entered, even though the patient may actually make the supply last much longer. Hard Patient scenario PRN Day Supply Patient uses sliding scale (average 4 units × 4 checks/day = 16 units/day) plus 20 units basal nightly. Both from a 1,000-unit vial. How many days does one vial last? Check Show solution **Answer: 27 days** Total daily: 16 (sliding scale) + 20 (basal) = 36 units/day. 1,000 ÷ 36 = 27.78 → **27 days** (round down). Hard Retail Complex Sigs Medrol Dosepak sig: 6 tabs Day 1, 5 tabs Day 2, 4 tabs Day 3, 3 tabs Day 4, 2 tabs Day 5, 1 tab Day 6. Total tablets and day supply for the complete Dosepak? A. 18 tablets — 5 daysB. 21 tablets — 6 daysC. 24 tablets — 7 daysD. 28 tablets — 7 days Show solution **Answer: 21 tablets — 6 days** 6+5+4+3+2+1 = **21 tablets** over **6 days**. Memorize: Medrol Dosepak = 21 tablets, 6 days. Hard Retail Complex Sigs Rx: "2 tabs BID × 7 days, then 1 tab BID × 7 days." Total tablets needed for the complete course? A. 21 tabletsB. 28 tabletsC. 42 tabletsD. 56 tablets Show solution **Answer: 42 tablets** Phase 1: 2 × 2 × 7 = 28. Phase 2: 1 × 2 × 7 = 14. Total: 28 + 14 = **42 tablets**. Hard Retail Complex Sigs Sig: "1-2 tabs Q4-6H PRN. Max 8 tabs in 24 hours." Qty: 60 tablets. Day supply using the stated maximum of 8 tabs per day? Check Show solution **Answer: 7 days** 60 ÷ 8 = 7.5 → **7 days** (round down). Hard Patient scenario Complex Sigs TB treatment: 2 tabs rifampin 300 mg QD × 2 months (60 days), then 1 tab QD × 4 months (120 days). Total 300 mg tablets for the complete 6-month course? A. 120 tabletsB. 180 tabletsC. 200 tabletsD. 240 tablets Show solution **Answer: 240 tablets** Phase 1: 2 × 60 = 120 tablets. Phase 2: 1 × 120 = 120 tablets. Total: 120 + 120 = **240 tablets**. **How this quiz works:** Pick your question count and difficulty, then start. After answering, click _Reveal explanation_ to see the full step-by-step solution — answers never show automatically. Score and type breakdown appear at the end. ⓘ This lesson has 32 questions in the bank. A 10-question quiz draws a random subset. Run multiple sets to cycle through all questions. How many questions? 102030 Question difficulty Random mixEasy onlyMedium onlyHard only Options Randomize question order Shuffle every time you start Timed mode 45-second countdown per question Number of sets Each set draws a fresh pool − 1 + 10 Questions 1 Sets 10 Total ~10 min Est. time ▶  Start quiz — Sig Interpretation Question 1 of 10 0 correct · 0 skipped \--% Score Quiz complete! Lesson 6 · Sig Interpretation · AlabamaPharmTech.com \-- Correct \-- Wrong \-- Skipped \-- Time Performance by question type \--% Overall accuracy \-- Weakest area Miss rate by question type Retry missed + skipped Next set New quiz Answer review — every question this session [Home](/) [Back to Dashboard](/modules) Previous [Back to Course](/pharmacy-math-practice) Lesson 6 of 6 Next lesson