CST Practice Test PDF (Free Printable 2026)

The CST exam is administered by NBSTSA — the National Board of Surgical Technology and Surgical Assisting — and it's one of the most technically demanding credentialing exams in allied health. You'll sit for 175 questions, but only 150 of them are scored; the remaining 25 are unscored pilot items scattered throughout. You won't know which are which. The passing threshold is a scaled score of 700, and you have 3 hours to finish.

That structure matters for your prep. Each question counts — or might not. That uncertainty makes it critical to answer everything confidently rather than gambling on which questions are "safe" to skip.

This page gives you a free printable PDF so you can work through practice questions away from a screen. Print it, take it to a quiet space, and time yourself. The PDF mirrors the format you'll see on test day.

What the CST Exam Actually Tests

The exam draws from four primary content domains. Here's what each one demands from you.

Perioperative Care

This domain covers everything that happens before the first incision and during the procedure itself. Preoperative patient assessment starts before the patient enters the OR — you need to know surgical site verification protocols, including the time-out procedure. That pre-incision pause isn't just a formality; it's a Joint Commission requirement, and NBSTSA tests whether you understand its components: patient identity, correct procedure, correct site.

Positioning is heavily tested. The four positions you must know cold are supine, prone, lateral, and lithotomy — and not just what they look like, but their associated complications. Lithotomy position puts patients at risk for compartment syndrome and peroneal nerve damage from prolonged compression. Prone positioning carries risks to the eyes, facial pressure points, and the brachial plexus. Know the padding requirements for each bony prominence.

Electrosurgical safety shows up every exam. You need to understand grounding pad placement — the pad goes on a large, well-vascularized muscle mass, away from bony prominences and implanted metal. The fire triad: oxygen source, ignition (the ESU), and fuel (drapes, prep solution vapors). Flammable prep solutions like alcohol-based chlorhexidine must fully dry before draping or the vapor can ignite.

Instrumentation, Equipment, and Supplies

Surgical instruments are organized by function, not by specialty. You need to think in categories.

Cutting and dissecting: scalpels (blade numbers — #10 for large incisions, #15 for fine work, #11 for stab incisions), scissors (Metzenbaum for tissue, Mayo for heavy tissue and suture), and osteotomes for bone.

Grasping and holding: hemostats (Kelly, Crile, mosquito — sized by jaw length), tissue forceps (smooth vs. toothed — toothed hold better but cause more damage), and clamps like Allis, Babcock, and Kocher.

Retracting: the distinction between self-retaining retractors (Balfour, Bookwalter, Weitlaner — they hold themselves open) and handheld retractors (Richardson, Army-Navy, malleable ribbon) that require someone to hold them. Self-retaining is more common in deep abdominal cases.

Instrument passing technique gets tested directly. When you pass an instrument to the surgeon, ratcheted instruments go with the ratchet open, handles pointed toward the surgeon's palm. The surgeon should be able to close and use the instrument without repositioning it. A poor pass slows the case and frustrates everyone.

Sterilization and Disinfection

Steam autoclave is the gold standard for heat-tolerant items. Two key parameter sets: gravity displacement cycles run at 250°F (121°C) and take 15–30 minutes depending on load. Prevacuum (dynamic air removal) cycles run at 270°F (132°C) and are faster — 3–4 minutes at temperature. Know which is which and why prevacuum is more reliable for porous loads.

Not everything can take heat. Chemical sterilants cover heat-sensitive scopes and specialty instruments. Glutaraldehyde (Cidex) is effective but requires a 10-hour soak for full sterilization — high-level disinfection takes 20–45 minutes. Peracetic acid systems (Steris) are faster and leave no toxic residue, which matters in instrument turnaround time.

Biological indicators are the only way to verify that sterilization actually worked. You're testing with bacterial spores — Geobacillus stearothermophilus for steam, Bacillus atrophaeus for EO gas. A positive BI result means you recall all loads processed since the last negative test.

Packaging matters too. Peel pouches are fine for single instruments — you peel them open toward the sterile field without touching the contents. Wrapped sets (muslin or SMS wrap) use sequential double-wrapping. Check for strike-through — moisture penetrating the wrap — before assuming a wrapped item is still sterile.

Surgical Procedures by Specialty

You don't need to memorize every specialty in depth, but you should know the standard setups for high-yield procedures.

Laparoscopic cholecystectomy (general surgery): CO2 insufflation, four trocar ports standard, clip applier for cystic duct and artery, electrosurgical hook dissector. Cholangiogram may be added. Patient position is supine with reverse Trendelenburg and left lateral tilt.

Total hip arthroplasty (orthopedics): lateral or posterior approach, large bone instruments including oscillating saw, reamers, broaches. Cement mixing and delivery if cemented prosthesis. Strict pulsatile lavage protocol before implant insertion. Hip dislocation precautions begin in the OR.

Cesarean section (OB-GYN): Pfannenstiel or midline incision, bladder blade retractor to protect the bladder, uterine incision with bandage scissors, bulb suction for immediate infant airway. Speed matters — baby out quickly, then uterine repair and closure.

CABG — coronary artery bypass graft (cardiovascular): median sternotomy, cardiopulmonary bypass with aortic cannulation and venous cannulation, cardioplegia to arrest the heart, internal mammary artery harvest or saphenous vein harvest, anastomosis with fine cardiovascular suture (Prolene 7-0 or 8-0). Certified surgical technologist candidates should expect 2–3 cardiovascular procedure questions on any given exam.

How to Use This PDF for Your Study Plan

Print the PDF and set a timer. Don't look anything up during your timed run — answer every question from memory, mark the ones you guessed on, and finish. Then score it.

The questions you marked as guesses tell you more than the ones you got wrong outright. A wrong answer you were confident about means a misconception to correct. A guess you got right means you got lucky — treat it as wrong and study that topic.

Build a rotation: one timed PDF session per week, with daily flashcard review of instrumentation categories and sterilization parameters. The CST rewards repetition on specifics — autoclave temperatures, instrument names, position complications.

Perioperative Care — Topics You Can't Skip

The time-out procedure is tested every cycle. Know all three required verifications: correct patient identity (two identifiers), correct procedure, correct surgical site. Some exams add a fourth — correct patient position. If a question describes a scenario where the time-out was skipped or abbreviated, the answer is almost always that the procedure should be stopped until the time-out is completed.

Positioning complications by position:

• Supine: pressure ulcers at occiput, scapulae, sacrum, heels. Heel padding is mandatory for long cases.
• Prone: facial pressure (eyes, nose, forehead), brachial plexus stretch if arms are positioned incorrectly, abdominal compression affecting ventilation.
• Lateral: brachial plexus injury from compression at the axilla — axillary roll placed just below the dependent axilla, not under it. Peroneal nerve compression at the fibular head on the dependent leg.
• Lithotomy: compartment syndrome from elevated legs (especially with prolonged cases), peroneal nerve damage, and post-op hip pain from hip flexion under anesthesia.

Electrosurgical units come in two modes. Monopolar ESU: current flows from the active electrode (pencil tip), through the patient's body, and exits at the dispersive electrode (grounding pad). The entire path is live — that's why pad placement matters so much. Bipolar ESU: current only flows between the two tips of the instrument. Safer near delicate structures like nerves. Lower heat, more precise. Can't cut — only coagulates.

Sterilization Parameters: The Numbers You Must Memorize

Flash sterilization (now called Immediate Use Steam Sterilization, or IUSS) is for dropped instruments that are needed immediately. It's not a substitute for standard sterilization cycles — no wrapped load, no biological indicator monitoring, not for implants. The exam tests whether you know the limitations of IUSS.

Ethylene oxide (EO) gas handles heat- and moisture-sensitive items — cameras, flexible scopes, some power tools. The catch: a 10–16 hour aeration period after the cycle to off-gas residual EO, which is toxic. Items sterilized with EO aren't available for same-day use.

High-level disinfection vs. sterilization: semi-critical items (items touching mucous membranes but not sterile tissue) require high-level disinfection, not full sterilization. Flexible endoscopes are the classic example — they get manual cleaning followed by automated endoscope reprocessing (AER) with a high-level disinfectant like OPA (ortho-phthalaldehyde) or peracetic acid.

What to Expect on Exam Day

NBSTSA CST testing happens at Prometric centers. You'll check in with government-issued ID, go through a security screening, and sit at an assigned workstation. The test is entirely computer-based — no paper, no reference materials.

175 questions in 3 hours. That's about 1 minute and 1 second per question. Comfortable — but don't let it make you careless. Use the flag function to mark questions you want to revisit. Answer everything, even if you're uncertain; there's no penalty for wrong answers.

The exam pulls from multiple content domains in a weighted distribution. Perioperative care and instrumentation together represent the largest portion of the scored questions. Sterilization and surgical procedures make up the rest. Don't underinvest in any domain — a score of 700 requires strength across all of them.

Results come quickly for computer-based testing. Unofficial pass/fail at the testing center, official score report from NBSTSA within a few weeks.

If you don't pass, you can retest. NBSTSA allows up to three attempts within a 12-month eligibility window. Each retest requires a new application fee. The waiting period between attempts is 90 days. Track your score report — it breaks down performance by content domain, so you know exactly where to focus your retake prep.

One more thing: the CST credential requires renewal every 4 years through continuing education (60 CE credits) or re-examination. Staying credentialed means staying current. The surgical environment changes — new sterilization technologies, updated positioning guidelines, revised safety protocols. The CE requirement keeps working STs current with those changes.