Cleaning, Decontamination and Disinfection is 21% of the scored CRCST exam. Answer 10 exam style questions on manual cleaning and IFUs and see exactly which concepts would cost you points on test day.
Start the 10 questions →A technician receives a new device and is unsure how to clean it. Which document is the primary source for its cleaning steps?
These questions cover IFU as the rule, disassembly, box locks and hinges, lumen brush sizing and cleaning brushes. Each one shows the correct answer and why every other option is wrong, so a miss tells you exactly what to review before the CRCST.
Prefer to read first? Every question from the practice set above, with the correct answer and why each wrong option is wrong.
Answer: B. The manufacturer's written instructions for use, or IFU, give the validated steps for disassembly, cleaning agents, brushes, and methods for that specific device. Department policies are built on IFUs, and when an IFU is missing the manufacturer is contacted before the device is processed.
Why not A: Similar devices can have very different validated cleaning steps.
Why not C: General posters do not cover the device specific requirements in an IFU.
Why not D: Preference cards list items for a procedure, not reprocessing instructions.
Exam tactic: When in doubt, IFU out. Read the instructions first.
Answer: A. Devices designed to come apart are disassembled before cleaning so detergent, brushes, and water can reach every surface, joint, and channel. Soil trapped between assembled parts cannot be removed and will shield organisms during sterilization.
Why not B: Disassembling after cleaning leaves the hidden surfaces uncleaned.
Why not C: Soil hidden between parts is not visible, so waiting for visible soil misses it.
Why not D: If the IFU calls for disassembly, the device is designed to be taken apart.
Exam tactic: If it comes apart, take it apart before cleaning.
Answer: C. Hinged instruments are cleaned in the open position so the box lock, hinge, and jaw serrations can be reached by detergent and brushes. The box lock is a common place for blood and tissue to hide.
Why not A: A closed ratchet keeps the box lock and jaws closed over soil.
Why not B: Closed jaws trap debris in the serrations.
Why not D: A tightly closed stringer forces instruments shut and blocks cleaning of the hinges.
Exam tactic: Open the box lock, unlock the dirt.
Answer: B. Lumen brushes must match the diameter and length specified in the IFU. A correct brush makes firm contact with the inner walls and passes through the full length of the channel. A brush that is too small misses the walls and one that is too large can damage the lumen.
Why not A: An oversized brush can bend, jam, or scratch the channel and does not clean evenly.
Why not C: The brush must reach the entire length of the lumen, not part of it.
Why not D: Bristles that do not touch the walls do not remove soil.
Exam tactic: Right brush = right diameter, right length, real contact.
Answer: D. Reusable brushes become contaminated with every use, so they are cleaned and then high-level disinfected or sterilized at least daily, or single-use brushes are discarded after use. Worn, bent, or matted brushes are replaced because they no longer clean effectively.
Why not A: Brushes left wet in a sink become a source of contamination.
Why not B: Brushes lose cleaning ability long before bristles fall out.
Why not C: Lumens differ in size, so one brush cannot fit them all correctly.
Exam tactic: Brushes get reprocessed too, at least daily.
Answer: A. Brushing loosens soil, but the debris stays inside the channel until it is flushed out. Lumens are flushed with detergent solution and then rinsed per IFU, for example with a syringe or flushing device. Brushing and flushing are repeated until the channel is clean.
Why not B: Room air does not remove debris and is not a validated drying or flushing method.
Why not C: Prolonged overnight soaking is not a validated step, lets soil resettle, and can damage instruments.
Why not D: Lubricant would trap the loosened soil inside the channel.
Exam tactic: Brush loosens, flush removes.
Answer: C. Blood and tissue are protein based. Hot water cooks these proteins so they harden and stick to the instrument, much like egg on a pan. A cool initial rinse keeps proteins soluble so they wash away.
Why not A: Rinsing is for removing soil, not killing organisms, and cool water is not more lethal.
Why not B: The concern with hot water is protein coagulation, not instant damage to the steel.
Why not D: Enzyme activity depends on the temperature range on the product label, and the cool rinse is not chosen to speed up enzymes.
Exam tactic: Hot water cooks blood. Start cool.
Answer: D. Soft nonabrasive brushes, such as nylon bristle brushes, remove soil without scratching the instrument surface. Abrasive tools damage the protective surface layer of stainless steel, leading to stains, pitting, and corrosion, and scratches create places for soil to hide.
Why not A: Steel wool scratches the surface and leaves metal particles behind.
Why not B: Wire bristles gouge the surface and damage the protective layer.
Why not C: Scouring powders scratch instruments and are hard to rinse away.
Exam tactic: Soft brush only. Scratches become hiding places.
Answer: B. Manual cleaning starts with a cool rinse to remove gross soil, then soaking and brushing in detergent solution, then a thorough rinse to remove soil and detergent residue. Items are then dried and inspected. The exact steps and times come from the device and detergent IFUs.
Why not A: Drying first sets the soil and the detergent step comes far too late.
Why not C: Drying between the soak and the brushing lets soil harden again.
Why not D: Rinsing must follow brushing, and inspection comes after drying, not before rinsing.
Exam tactic: Rinse, wash, rinse, dry, look.
Answer: B. Rinsing removes loosened soil and detergent residue. Residue left on devices can stain or damage instruments, interfere with sterilization, and cause tissue reactions in patients. The IFU sets the rinse water quality and volume.
Why not A: Rinsing is not used to warm instruments.
Why not C: The detergent has already done its work and its residue must now be removed.
Why not D: Items still need drying after rinsing to prevent spotting and corrosion.
Exam tactic: Detergent cleans, rinse takes it all away.
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