Pharmacy Abbreviations Quiz: 20 Free Questions With Answers
Published 2026-11-05 · Facts and text checked 2026-11-02 · Questions from our PTCB study guide · Reviewed by Hana N., Quality Reviewer
This free Pharmacy Abbreviations Quiz has 20 questions from the practice tests in our PTCB study guide, on the sig codes and abbreviations you read on a prescription. Click an answer to see if it is right and read the explanation, then check your result against our study target.
Sig codes and the abbreviations you must read on a prescription, including error-prone ones. On the exam this is part of 4. Order Entry and Processing (22.50%). Open each answer to read the explanation.
Question 1Medium
Why must the word 'units' be written out instead of the abbreviation 'U' in a medication order?
Show answer and explanation
Correct answer: D. U can be misread as a zero, four, or six, causing a tenfold overdose.
A handwritten U can look like 0, 4, or 6, so a dose of 10U can be read as 100 or 104, causing a serious overdose. Writing the full word 'units' removes this ambiguity.
From practice test 13 of our PTCB study guide (question 19). Original question, not an official exam item.
Question 2Easy
Which abbreviation is on The Joint Commission Do Not Use list primarily because it can mean either morphine sulfate or magnesium sulfate?
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Correct answer: C. MS
MS is on the Do Not Use list because it can mean either morphine sulfate or magnesium sulfate. MSO4 and MgSO4 are also prohibited but are specifically confused with each other, not with MS.
From practice test 4 of our PTCB study guide (question 52). Original question, not an official exam item.
Question 3Easy
On a pharmacy insurance card, what does the abbreviation 'BIN' stand for?
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Correct answer: D. Bank Identification Number
BIN is the Bank Identification Number, a six-digit code that routes the claim to the correct claims processor. The other options are not the accepted meaning.
From practice test 11 of our PTCB study guide (question 28). Original question, not an official exam item.
Question 4Medium
Which two abbreviations are on The Joint Commission's Do Not Use list because the period after the Q can be misread as an I, turning once daily into four times daily?
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Correct answer: C. Q.D. and Q.O.D.
The periods in Q.D. and Q.O.D. can be misread as the letter I, turning once daily into QID, four times daily. The Joint Commission requires daily and every other day to be written in full.
From practice test 14 of our PTCB study guide (question 23). Original question, not an official exam item.
Question 5Medium
A prescriber writes '2 mg Q.D.' in an order. Which of the following errors is this abbreviation most likely to cause?
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Correct answer: D. The 'Q.D.' is read as 'QID', leading to a fourfold increase in dosing frequency.
The period after the Q in Q.D. can be misinterpreted as an I, changing the abbreviation to QID, which means four times daily instead of once daily. This is exactly why Q.D. is prohibited.
From practice test 16 of our PTCB study guide (question 53). Original question, not an official exam item.
Question 6Medium
Why are both 'Q.D.' and 'Q.O.D.' on The Joint Commission's Do Not Use list?
Show answer and explanation
Correct answer: B. Because Q.D. and Q.O.D. can both be misread as QID, which means four times daily
The period after the Q can be read as an I, turning Q.D. into QID, and the O in Q.O.D. can also be read as an I. Both errors create a fourfold dosing error, so the abbreviations must be written as 'daily' and 'every other day' in full.
From practice test 9 of our PTCB study guide (question 64). Original question, not an official exam item.
Question 7Medium
Which of the following abbreviations is NOT included on The Joint Commission's official Do Not Use list?
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Correct answer: A. mcg
The Do Not Use list contains U, IU, Q.D., Q.O.D., trailing zeros, leading decimal points, MS, MSO4, and MgSO4. Abbreviation mcg is not on the list, although writing out microgram is often preferred for safety.
From practice test 16 of our PTCB study guide (question 26). Original question, not an official exam item.
Question 8Medium
Why is the abbreviation MS prohibited on medication orders and labels?
Show answer and explanation
Correct answer: B. It can mean morphine sulfate or magnesium sulfate, two drugs with very different effects.
MS is ambiguous because it can stand for either morphine sulfate or magnesium sulfate, and those drugs have different mechanisms and doses. Writing the full drug name removes the ambiguity.
From practice test 6 of our PTCB study guide (question 40). Original question, not an official exam item.
Question 9Easy
Why must the full word 'units' be written instead of the abbreviation 'U' on medication orders and labels?
Show answer and explanation
Correct answer: B. U can look like a zero, four, or six, which can lead to a tenfold overdose
The letter U can be misread as a zero, four, or six, turning 10U into 100 or 104 and causing a tenfold overdose. The rule exists to eliminate this specific visual ambiguity.
From practice test 10 of our PTCB study guide (question 20). Original question, not an official exam item.
Question 10Easy
Why must the abbreviation IU be avoided in medication orders?
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Correct answer: D. IU can be mistaken for IV or the number 10
IU looks like 'IV' or '10', which can lead to a wrong route or a wrong dose. Write 'international units' or 'units' in full.
From practice test 2 of our PTCB study guide (question 50). Original question, not an official exam item.
Question 11Medium
While entering a new prescription, a technician sees the pharmacy system auto-fill the sig code as 'once daily' because that was the last entry for this medication. The prescriber actually wrote 'take one tablet by mouth every 12 hours for 10 days.' What should the technician do?
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Correct answer: C. Override the default and enter the exact directions from the prescription
Default sig codes are previous entries, not a source of truth for the current order. The technician must translate exactly what the prescriber wrote, so the default must be overridden with the correct directions. Accepting the default would apply the wrong frequency to the label.
From practice test 11 of our PTCB study guide (question 56). Original question, not an official exam item.
Question 12Easy
A prescriber writes 'MS 2 mg IV' on a medication order. Why is this abbreviation considered unsafe?
Show answer and explanation
Correct answer: A. MS can mean either morphine sulfate or magnesium sulfate, two drugs with very different effects and doses.
The Joint Commission prohibits 'MS' because it is ambiguous between morphine sulfate and magnesium sulfate, which have different indications, doses, and risks. Adding a dose does not remove the ambiguity, so the full drug name must be written.
From practice test 3 of our PTCB study guide (question 44). Original question, not an official exam item.
Question 13Easy
Why are the abbreviations MS, MSO4, and MgSO4 included on The Joint Commission's Do Not Use list?
Show answer and explanation
Correct answer: C. They can be confused with one another because MS is ambiguous between morphine sulfate and magnesium sulfate
MS is ambiguous because it can mean morphine sulfate or magnesium sulfate, and MSO4 and MgSO4 are easily confused with each other. The Do Not Use list requires writing the complete drug names.
From practice test 14 of our PTCB study guide (question 88). Original question, not an official exam item.
Question 14Medium
A prescriber writes 'Q.D.' for a medication that should be given once daily. Why does the Joint Commission prohibit this abbreviation?
Show answer and explanation
Correct answer: A. The period after the Q can be misread as an I, turning Q.D. into Q.I.D., which changes once daily to four times daily and causes a fourfold overdose
The period after the Q can look like an I, so Q.D. can be read as Q.I.D., meaning four times daily instead of once daily. That produces a fourfold overdose, so the abbreviation is prohibited.
From practice test 8 of our PTCB study guide (question 18). Original question, not an official exam item.
Question 15Medium
A handwritten order reads '10U' of insulin. Why is this abbreviation dangerous?
Show answer and explanation
Correct answer: A. U can be misread as a zero, four, or six, potentially turning 10U into 100, 104, or 106 units
The Joint Commission prohibits 'U' because it can be misread as '0', '4', or '6', causing a tenfold or larger overdose. The full word 'units' must be written.
From practice test 2 of our PTCB study guide (question 26). Original question, not an official exam item.
Question 16Easy
Which of the following is the correct replacement for the prohibited abbreviation Q.D.?
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Correct answer: B. daily
Q.D. is prohibited because it can be misread as QID, meaning four times daily. The Joint Commission requires writing the word daily in full.
From practice test 14 of our PTCB study guide (question 74). Original question, not an official exam item.
Question 17Medium
A prescriber writes 'Q.D.' for one medication and 'Q.O.D.' for another. What is the main reason both abbreviations are prohibited?
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Correct answer: D. Q.D. means once daily and Q.O.D. means every other day, but the period after Q and the O in Q.O.D. can each be misread as I, turning either into QID (four times daily)
Q.D. and Q.O.D. are prohibited because they can be misread as QID, meaning four times daily, which creates a fourfold dosing error. Full words such as 'daily' and 'every other day' must be used.
From practice test 15 of our PTCB study guide (question 34). Original question, not an official exam item.
Question 18Medium
Why is the abbreviation MS on The Joint Commission's Do Not Use list?
Show answer and explanation
Correct answer: A. It is ambiguous because it can mean morphine sulfate or magnesium sulfate.
MS is banned because it has two possible meanings with very different doses. The full drug name must always be written.
From practice test 11 of our PTCB study guide (question 36). Original question, not an official exam item.
Question 19Easy
A pharmacy technician sees a prescription written with 'mcg' for microgram. Which statement correctly describes the status of this abbreviation?
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Correct answer: A. It is not on the Do Not Use list, though writing 'microgram' in full is safer
The Do Not Use list contains U, IU, Q.D., Q.O.D., trailing and leading decimal errors, MS, MSO4, and MgSO4; mcg is not on it. Because sloppy handwriting can make mcg look like mg, writing microgram in full is safer, but it is not forbidden.
From practice test 7 of our PTCB study guide (question 81). Original question, not an official exam item.
Question 20Easy
Why are the abbreviations 'MS' and 'MSO4' included on The Joint Commission Do Not Use list?
Show answer and explanation
Correct answer: B. They are ambiguous between morphine sulfate and magnesium sulfate, which have very different effects and doses.
MS and MSO4 can mean either morphine sulfate or magnesium sulfate, two drugs with very different clinical effects and dose ranges. The full drug names must be written out.
From practice test 12 of our PTCB study guide (question 31). Original question, not an official exam item.
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