Want to test your science knowledge before the CRCST exam? Below are free sample flashcards from the 60-card science section of our 1090-card CRCST (Certified Registered Central Service Technician) deck.
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Identify the spherical bacteria that typically occur in grape-like clusters frequently associated with surgical site infections and found on human skin.
Show answer →Staphylococcus aureus. These are Gram-positive cocci. HSPA emphasizes knowing shapes: Cocci (round), Bacillus (rod), and Spirillum (spiral). Clusters = Staphylo; Chains = Strepto. Clinical Pearl: S. aureus is a major concern in Sterile Processing due to its prevalence in SSIs and its ability to survive on environmental surfaces.
Which structural component of a Gram-negative bacterial cell wall makes it more resistant to certain disinfectants compared to Gram-positive bacteria?
Show answer →The Outer Membrane. Gram-negative bacteria have a complex cell wall containing an outer lipopolysaccharide (LPS) layer. Gram-positive bacteria have a thick peptidoglycan layer but lack this outer membrane. HSPA Tip: Remember that the outer membrane acts as a barrier to some chemicals, often making Gram-negatives harder to kill with certain low-level disinfectants compared to Gram-positives like MRSA or VRE.
Why are Geobacillus stearothermophilus spores used as the gold standard for biological monitoring in steam sterilizers?
Show answer →Extreme resistance. Spores (endospores) are a dormant, highly resistant state of certain bacteria (like Bacillus and Clostridium). They have a thick protective coat that resists heat, chemicals, and radiation. G. stearothermophilus is highly heat-resistant, making it the ideal challenge for steam sterilization. Exam Strategy: If the spore is killed, all other vegetative microorganisms are assumed dead.
A technician is processing instruments used on a patient with a deep tissue abscess where Clostridium perfringens is suspected. What is a key characteristic of this organism?
Show answer →It is an Obligate Anaerobe. Anaerobic bacteria grow in the absence of free oxygen. Clostridium species are also spore-formers. Exam Strategy: HSPA often tests the oxygen requirements—Aerobes (need O2), Anaerobes (no O2), and Facultative Anaerobes (can do both). C. perfringens is associated with gas gangrene and requires meticulous cleaning and sterilization.
During the bacterial growth cycle, in which phase do bacteria divide most rapidly, making them most susceptible to certain disinfection processes?
Show answer →Log Phase (Exponential Phase). Phases: 1. Lag (preparing to grow), 2. Log (rapid division), 3. Stationary (growth equals death), 4. Decline/Death. Clinical Pearl: Bacteria are most metabolically active during the Log phase. Understanding growth helps SP techs realize why immediate cleaning (point-of-use treatment) is vital to prevent bacteria from reaching high populations.
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Try 30 free CRCST cards firstThe full CRCST deck contains 1090 flashcards, and 60 of them focus on science. This page shows 5 free samples.
Our CRCST deck dedicates 60 of 1090 cards (6%) to science — always cross-check the official HSPA exam outline for the current blueprint weighting.
Yes — the samples on this page are free, and the CRCST preview page has 30 more free cards. Full access to all 1090 cards is a one-time $7.
Anatomy
60 cards
Decontamination
180 cards
Equipment
80 cards
Monitoring
60 cards
Packaging
70 cards
Regulations
80 cards
Safety
60 cards
Sterilization
140 cards
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