Microbiology Practice Questions for the CST
Microbiology is 6 of the 150 scored questions. It applies microbiology to the operating room: the organisms that cause surgical infections, infection control, how tissue is handled, how wounds heal and how they are classified.
175 questions across every content area in 4 hours, with a score for microbiology and your total against the 98-of-150 passing score.
Free microbiology drill- 31 original microbiology questions, each explained
- 6 of 150 scored questions on the real exam (outline III.B)
- Basic Science content area (20% of the exam)
Which is one of Halsted's principles of tissue handling?
What our microbiology questions cover
- Classification and pathogenesis of microorganisms, cultures and specimens
- Infection control procedures such as aseptic technique
- Principles of tissue handling: Halsted’s principles and traction and countertraction
- Stages of wound healing and the factors that affect it
- Surgical wound classification (Class I clean to Class IV dirty or infected)
- Factors that influence an infectious process
This list is our own summary of the outline tasks, written for practice. NBSTSA publishes the full task list in the CST Examination Content Outline.
Drill microbiology, then sit the full exam
175 questions across every content area in 4 hours, with a score for microbiology and your total against the 98-of-150 passing score.
Free microbiology drillIdeas the questions test most
- Staphylococcus aureus is the most common cause of surgical site infections.
- Endospores are the most resistant form of microbial life; C. difficile spores need soap and water.
- An elective cholecystectomy is Class II; a perforated appendix with pus is Class IV.
Start the free microbiology drill · Basic Science drill · Full 175-question mock exam
Common questions
How many CST questions cover microbiology?
Microbiology is 6 of the 150 scored questions, part of the Basic Science content area.
Do I need to know wound classes for the CST?
Yes. Surgical wound classification is listed in the outline. Know the four CDC classes and an example of each.
175 questions across every content area in 4 hours, with a score for microbiology and your total against the 98-of-150 passing score.
Free microbiology drillMore CST subject areas
- Preoperative Preparation · Perioperative Care
- Intraoperative Procedures · Perioperative Care
- Postoperative Procedures · Perioperative Care
- Administrative and Personnel · Ancillary Duties
- Sterilization and Equipment · Ancillary Duties
- Anatomy and Physiology · Basic Science
- Surgical Pharmacology · Basic Science
- Surgical Instruments · Perioperative Care
Content areas, subject areas, item counts and tasks: NBSTSA: CST certification (format, passing score, content areas) · NBSTSA: CST Examination Content Outline, checked November 2026.
CST® and Certified Surgical Technologist® are registered marks of the National Board of Surgical Technology and Surgical Assisting (NBSTSA). Independent practice, not affiliated with or endorsed by NBSTSA, the Association of Surgical Technologists (AST) or PSI. Our questions are original and are not taken from the CST exam.