CST Practice Tests: NBSTSA's Forms A and B, the $75 Practice Exam Hub, and 5 Original Questions

Only two kinds of full CST practice test come from NBSTSA, and both cost money, though programs receive free vouchers for Forms A and B: the Self-Assessment Forms A and B sold through PSI, and NBSTSA's new Practice Exam Hub, which isn't on sale yet. Everything else, including free online sets, is unofficial. That doesn't make it useless, but it changes how you should judge it.

Official CST practice tests, as checked on October 28, 2026

The details come from PSI's product pages for Form A and Form B, NBSTSA's prepare page and its educator FAQs. A few rules are easy to miss:

• Forms A and B can be graded once. NBSTSA's page for educators says you can log in and out for 30 days but grade the exam only one time. Grading gives an analysis of individual questions and of your performance, which you can print.
• Programs get free vouchers. The same page says each program receives two practice exam vouchers at the start of the test form year, which it dates to August 1. Ask your program director before you pay.
• The Hub repeats itself in year one. The educator FAQs say you can buy additional Hub tests at $75 each, but the questions stay the same for the first year.
• None of it affects your result. NBSTSA says practice performance doesn't affect eligibility and isn't part of your certification record. PSI's pages add that the products give no advantage in administration or scoring.

One inconsistency: the study tips in the 2026 candidate handbook still mention practice exams on nbstsa.org and a mobile study app with over 300 questions, while the prepare page now calls the Practice Exam Hub the only study tool NBSTSA offers directly. Go by the prepare page and PSI's store when you buy.

Using Forms A and B and the Practice Exam Hub as checkpoints (Passy approach)

Each form gives you one graded attempt, so use them as checkpoints, not as drills. A practical schedule:

1. Form A at the midpoint of your study plan. Its question analysis shows which sub-areas need the second half of your time.
2. Form B about one to two weeks before the exam. Late enough to measure what changed, early enough to fix it.
3. The Hub, if you test in 2027 or later. It is built for one three-hour sitting of 150 questions, about 72 seconds per question (Passy arithmetic). The real exam gives you 4 hours for 175 questions, about 82 seconds each, so a Hub sitting is slightly tighter than test day.

Neither official option gives you all 175 questions under the full 4-hour clock. NBSTSA's On Test Day page also sets a rule to build into any timed run: after a break, you can't go back to questions you already answered, so finish your reviews before you stand up. For pacing across the full length, rehearse the 4-hour clock with the planned 175-question CST mock exam.

What CST questions look like, by NBSTSA's own numbers

NBSTSA's exam development guide classifies every item as recall ("What is X?") or application ("Given the following information about Y, what is X?"). The 2023 job analysis report shows how the committee judged the split for each subject area:

Some Passy arithmetic: those shares work out to about 89 application items out of 150, roughly 59% of the scored exam. NBSTSA's page on how it sets the standard states the same 71% figure for Perioperative Care.

What else NBSTSA's documents say about the items:

• They should describe realistic, practical situations and measure a single objective each.
• They avoid regional terms, including instrument names used only in some places, so the name on the screen may not be the one your hospital uses.
• The outline's five sample questions each have four options, A to D, and ask for the one best answer. Two use a capitalized qualifier, ESSENTIAL or MOST, which is a signal to read every option before choosing.

So a practice set that is mostly definitions will feel easier than the exam's Perioperative Care section. Good practice for those 97 items puts you in a case and asks what to do next.

Free CST practice, and why recalled questions are off limits

Free sets can help with recall, especially for Basic Science, but check three things before trusting one:

• Does it match current facts? A set that says the exam is 3 hours or that you need 70% doesn't match NBSTSA's current pages, which list 4 hours and 98 correct of 150 scored questions.
• Does it explain the wrong options? On application items, knowing why the near-miss option fails is most of the learning.
• Does it map to the outline? If you can't tell which sub-area a question belongs to, you can't use your results to plan.

Avoid anything sold or shared as "recalled" or "actual" exam questions. NBSTSA's On Test Day page says all exam content is copyrighted and that sharing or reproducing questions in any form is illegal. Its policies list unauthorized possession or distribution of exam materials, including reproduced questions, among the grounds for denying or revoking certification.

If you want scenario practice organized the way the exam is, practice planned for launch covers all three NBSTSA subject areas, one at a time or mixed.

Five original CST-style questions, written by Passy

These are Passy's own questions, written for this guide. They are not NBSTSA items and don't come from any exam or practice test. Each one follows a source opened for this guide.

Question 1: Equipment Sterilization and Maintenance

The daily air-removal (Bowie-Dick) test in a prevacuum steam sterilizer shows a spot in the center of the test sheet that didn't change color. What should happen next?

• A. Run the first instrument load and watch the printout closely
• B. Keep the sterilizer out of use until it is inspected and passes
• C. Accept the result, because the weekly spore test will confirm it
• D. Use the sterilizer for wrapped trays but not for implant loads

Keyed answer: B. CDC's steam sterilization page says entrapped air causes a spot on the test sheet and that a sterilizer that fails the Bowie-Dick test should not be used until maintenance personnel inspect it and it passes. A and D keep using a sterilizer that failed. C is wrong because a spore test doesn't replace the daily air-removal check.

Question 2: Intraoperative Procedures

Midway through a long abdominal case, the scrub CST is being permanently relieved by another CST. What should happen as part of the handoff?

• A. A count is performed with the circulator at the handoff
• B. Counting waits until the closing count before skin closure
• C. The departing CST signs the count sheet as correct and leaves
• D. The circulator counts alone after the new CST has scrubbed in

Keyed answer: A. The counting procedure in The Joint Commission's Sentinel Event Alert 51 includes a count at the permanent relief of either the scrub person or the circulating nurse, performed audibly and visibly by two people. B skips a required count point, C documents a count nobody performed, and D drops the second person.

Question 3: Surgical Pharmacology

A healthy 70-kg adult is having local infiltration with 1% lidocaine without epinephrine. Using the maximum doses in the Xylocaine label, what is the most that may be given?

• A. 15 mL (150 mg)
• B. 30 mL (300 mg)
• C. 31.5 mL (315 mg)
• D. 49 mL (490 mg)

Keyed answer: B. The Xylocaine label sets 4.5 mg/kg for lidocaine without epinephrine and says the total should generally not exceed 300 mg. 4.5 × 70 is 315 mg, so the 300 mg cap applies, and a 1% solution holds 10 mg per mL, so 300 mg is 30 mL. C ignores the cap, D uses the 7 mg/kg limit for lidocaine with epinephrine, and A is half the maximum.

Question 4: Preoperative Preparation

A patient is having a mastectomy by a general surgeon, followed under the same anesthetic by breast reconstruction performed by a plastic surgeon. When is a time-out required?

• A. Only once, before the first incision of the day
• B. Before each procedure, since the person performing it changes
• C. Only before the second procedure, since it is the longer one
• D. Only if the second procedure is on a different body site

Keyed answer: B. The Joint Commission's 2026 National Performance Goals for hospitals say that when two or more procedures are performed on the same patient and the person performing the procedure changes, a time-out is performed before each one. The other options invent conditions the goal doesn't contain.

Question 5: Microbiology and infection control

Under the Spaulding classification that CDC uses, which of these items is semicritical, needing at least high-level disinfection before reuse?

• A. A laryngoscope blade
• B. A blood pressure cuff
• C. A urinary catheter
• D. A surgical retractor

Keyed answer: A. CDC's rational approach page lists laryngoscope blades as semicritical, items that contact mucous membranes, and says semicritical items minimally require high-level disinfection. A blood pressure cuff touches intact skin, so it is noncritical. Urinary catheters and surgical instruments are critical items that must be sterile.

To keep going with explained items like these, work through 975 planned CST questions, each with an explanation, once full prep launches.

Reviewing a CST practice test so the next one goes better

A score on its own tells you little. After any practice set, official or not, sort each miss in three ways:

1. By sub-area. Use the eight sub-areas of the outline. The CST content outline guide shows how many scored items each one carries, so a miss in Intraoperative Procedures weighs more than a miss in Microbiology.
2. By question type. Was it a fact you didn't know (recall) or a decision you got wrong with the facts in front of you (application)? Recall misses go to flashcards. Application misses need a reread of the procedure or rule, then a new scenario.
3. By cause. Didn't know it, misread a qualifier such as MOST or FIRST, or changed a right answer. The last two are pacing and reading habits, not knowledge gaps.

Then redo NBSTSA's free Study Evaluation, rating each sub-area from 1 (very knowledgeable) to 5 (not knowledgeable), and shift your time toward the 3s, 4s and 5s.

Your next step with CST practice questions

Take the 20 free CST practice questions today and sort your misses with the three-way method above. Then build the official forms into your calendar: the CST study plan guide places Form A at the midpoint and Form B in the last two weeks, and the free CST study planner fits the weeks to your test date.