21 Aseptic Technique & Cleaning Practice Questions & Answers

1. 1. What does the principle of "first air" require during aseptic manipulation inside a primary engineering control?

   • A.Room air must pass through the filter twice before reaching the work zone.
   • B.The HEPA filter itself must be disinfected before each compounding session.
   • C.Nothing may be placed between the HEPA filter and any critical site.✓ Answer
   • D.The first preparation of each shift must be made closest to the filter face.

   First air is the HEPA-filtered air at the moment it leaves the filter, before it has touched anything, so it is the cleanest air available. Any object in its path becomes the last surface the air contacts before reaching the critical site, so contamination from that object is carried directly onto the site; the line between filter and critical site must therefore stay clear.

   Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, first air and critical sites in a primary engineering controlReport a problem with this question

2. 2. A stack of supplies sits directly between the airflow source and the open injection port of an intravenous bag. What has the compounder created?

   • A.A pressure change that directs filtered air more squarely onto the port.
   • B.A pocket of still air that filtered air keeps sterile until the item moves.
   • C.A downstream zone of turbulent, possibly contaminated air that reaches the port.✓ Answer
   • D.A rise in air velocity that sweeps particles away from the injection port.

   Unidirectional air breaks up when it strikes an object, and the wake behind that object is a zone of turbulence in which room air and particles can be entrained. Because that disturbed air is what then reaches the injection port, supplies are spaced apart and nothing is ever set between the filter and a critical site.

   Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, airflow obstruction and zones of turbulence within a primary engineering controlReport a problem with this question

3. 3. In a horizontal-flow laminar airflow workbench, filtered air travels from the rear filter face toward the compounder. Where must hands and supplies never be placed?

   • A.Upstream of the critical site, between it and the filter.✓ Answer
   • B.Above the critical site, in the space situated just over it.
   • C.Beside the critical site, at the same level on the work surface.
   • D.Downstream of the critical site, closer to the opening.

   The forbidden position is always the one upstream of the critical site, because that is where an object can shed onto air that has not yet reached the site. In horizontal flow the upstream direction is toward the rear filter, so a hand behind a vial or port blocks first air; in a vertical-flow device the same error is a hand held above the site.

   Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, placement of hands and materials in a horizontal-flow laminar airflow workbenchReport a problem with this question

4. 4. Inside a biological safety cabinet, HEPA-filtered air flows downward across the work surface. Which hand position interrupts first air to a critical site?

   • A.A hand held beside the critical site on the work surface.
   • B.A hand held behind the critical site near the rear wall.
   • C.A hand held in front of the critical site near the sash.
   • D.A hand held over the critical site while it is opened.✓ Answer

   The geometry of the hazard follows the direction of the airflow, not a fixed compass point. Because a biological safety cabinet supplies air from above, anything held over the critical site is upstream of it and its shed particles are carried straight down onto the site, which is why work is done to the side of open ports and stoppers rather than over them.

   Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, placement of hands and materials in a vertical-flow containment deviceReport a problem with this question

5. 5. A technician works close to the front opening of the workbench and reaches in and out rapidly to fetch supplies. What is the main hazard of doing this?

   • A.Disinfectant residue evaporates faster than it can be reapplied.
   • B.Room air that is not filtered is pulled in over the critical sites.✓ Answer
   • C.The blower motor slows until it compensates for the extra movement.
   • D.Static charge builds on the work surface and attracts glass particles.

   The unidirectional air stream is weakest and most easily disturbed at the open edge of the device, and fast in-and-out motion drags room air backward into the work zone. Manipulations are therefore performed well inside the workbench, with slow and deliberate movements and supplies staged in advance so the compounder does not keep crossing the air curtain.

   Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, maintaining unidirectional airflow and minimizing turbulence during aseptic manipulationReport a problem with this question

6. 6. Which of the following is a critical site that must be disinfected with sterile alcohol before it is entered?

   • A.The corrugated carton that the vials arrived in.
   • B.The outer plastic overwrap around a fluid bag.
   • C.The printed paper label on the side of the vial.
   • D.The rubber stopper on top of a sealed drug vial.✓ Answer

   A critical site is any opening or surface that, once contaminated, gives organisms direct access to the preparation: vial stoppers, ampule necks, needle hubs, syringe tips and plungers, injection ports and tubing spikes. Labels and overwraps are outer packaging, and corrugated cartons shed fibers and are removed before supplies enter the compounding area.

   Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, identification and disinfection of critical sitesReport a problem with this question

7. 7. A vial stopper has been swabbed with a sterile alcohol wipe. Why must it be allowed to dry before the needle is introduced?

   • A.Alcohol left on the stopper would chemically inactivate the drug inside.
   • B.The alcohol works as it acts and evaporates, and a wet surface carries organisms in.✓ Answer
   • C.A stopper that is still wet is much more likely to core when a needle enters.
   • D.Drying restores the elasticity the rubber stopper needs in order to reseal.

   Wiping only spreads the alcohol; the microbial kill happens over the seconds the alcohol is in contact with the surface and evaporates. If the needle goes through while the stopper is still wet, surviving organisms suspended in that liquid film can be carried on the needle into the vial, so drying — not the wiping motion — is what accomplishes the disinfection.

   Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, critical-site disinfection with sterile alcohol and drying before entryReport a problem with this question

8. 8. A needle is pushed straight down through a vial stopper using heavy force. What is the most likely consequence?

   • A.A fragment of the rubber stopper is pushed into the vial solution.✓ Answer
   • B.The needle bevel dulls so the syringe can no longer fill evenly.
   • C.The solution is forced out of the vial onto the work surface.
   • D.The stopper seals so tightly that the vial can no longer be entered.

   Straight-down force lets the bevel punch out a plug of rubber, which is called coring and puts particulate matter into a solution destined for injection. The needle is instead placed bevel up against the stopper at an angle and brought upright as it passes through; if coring is seen or suspected, the vial and any affected preparation are quarantined and discarded rather than filtered and used.

   Source: PTCB CSPT Content Outline, Sterile Compounding Procedures — aseptic manipulation of vials and prevention of coringReport a problem with this question

9. 9. Before withdrawing solution from a sealed non-hazardous vial, the compounder injects a matching volume of filtered air. What does this accomplish?

   • A.It dissolves any drug that has settled at the bottom of the vial.
   • B.It pushes the drug out faster so that the step takes less time.
   • C.It drives out air bubbles clinging to the inner wall of the vial.
   • D.It keeps pressure in the vial balanced as fluid is withdrawn.✓ Answer

   Removing liquid from a sealed container without replacing the volume creates a vacuum that resists the plunger, pulls air past the needle and makes the measured volume inaccurate; adding too much air instead sprays drug out of the needle when it is withdrawn. Hazardous drugs reverse the goal: the vial is kept slightly negative and a closed-system transfer device is used so nothing escapes.

   Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, vial entry and pressure equalization during aseptic transferReport a problem with this question

10. 10. The neck of a glass ampule has been swabbed with sterile alcohol and has dried. What is the correct next action?

    • A.Grip the neck with the bare fingers and snap it toward the filtered air source.
    • B.Wrap the neck in a sterile wipe and snap it away from the face and filter.✓ Answer
    • C.Score the neck with a blade and rinse the cut edge with sterile water.
    • D.Invert the ampule and tap its neck against the work surface to open it.

    The sterile wipe protects the gloved fingers from the fracture edge and contains any spray, and snapping away from the face and away from the direction of the incoming air keeps glass and aerosol out of the operator's breathing zone and out of the first air. An ampule is an open, single-use system: it is never re-entered, never stored, and never taped shut for later use.

    Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, ampule preparation and opening techniqueReport a problem with this question

11. 11. A lyophilized powder has been reconstituted with diluent. Before any volume is withdrawn, the compounder must confirm that:

    • A.the powder is fully dissolved, with no undissolved drug in the vial.✓ Answer
    • B.the diluent used was bacteriostatic water, whatever the route ordered.
    • C.the vial has been chilled in the refrigerator before it is measured.
    • D.the vial has been shaken hard until foam covers the whole solution.

    Until the powder is completely in solution the concentration is not uniform, so any volume withdrawn contains an unknown and usually low amount of drug, and undissolved particles could be injected. The vial is swirled or rolled gently and inspected against light before withdrawal; protein and biologic products are never shaken hard, because agitation denatures them and the foam it creates makes accurate measurement impossible.

    Source: PTCB CSPT Content Outline, Sterile Compounding Procedures — reconstitution of lyophilized drug productsReport a problem with this question

12. 12. Sterile isopropyl alcohol is used on surfaces inside the primary engineering control. Which statement accurately describes what it does?

    • A.It disinfects surfaces but does not clean soil or kill spores.✓ Answer
    • B.It kills bacterial spores, so a sporicidal agent is unnecessary.
    • C.It cleans soil from surfaces, so no detergent step is required.
    • D.It sterilizes the surface, so wiping alone renders it sterile.

    The agent categories do different jobs: a cleaner with detergency lifts soil and residue, a disinfectant kills vegetative organisms, and a sporicidal agent kills bacterial spores that survive ordinary disinfection. Alcohol belongs only to the second category, so it is used after cleaning and to remove residue, and it can never substitute for the germicidal detergent step or for the scheduled sporicidal application.

    Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, cleaning, disinfecting, and sporicidal agentsReport a problem with this question

13. 13. A containment primary engineering control has been used for a hazardous drug batch. In what order are the surface treatments applied afterward?

    • A.Disinfect, then deactivate, then decontaminate, then clean.
    • B.Decontaminate, then clean, then disinfect, then deactivate.
    • C.Clean, then disinfect, then deactivate, then decontaminate.
    • D.Deactivate, then decontaminate, then clean, then disinfect.✓ Answer

    Each step prepares the surface for the next one. Deactivation renders the drug residue chemically less hazardous, decontamination physically removes that residue, cleaning then lifts remaining soil, and only a clean surface can be reliably disinfected; wiping a surface that still bears active drug simply spreads it and exposes the compounder, and a sporicidal agent is applied separately on the required schedule.

    Source: USP General Chapter <800> Hazardous Drugs — Handling in Healthcare Settings, deactivation, decontamination, cleaning, and disinfection of containment equipmentReport a problem with this question

14. 14. How is the interior of a horizontal-flow workbench wiped during routine cleaning?

    • A.From the filter face out toward the opening, in overlapping strokes.✓ Answer
    • B.From the centre outward to both sides, in a single circular motion.
    • C.From the work surface upward to the top of the cabinet interior.
    • D.From the opening inward toward the filter face, in overlapping strokes.

    Cleaning always moves from the cleanest area toward the dirtiest and from top to bottom, so soil is never dragged back into the zone that must stay cleanest. In a horizontal device the cleanest zone is the filter face, so the sequence runs bar, back wall, sides and finally the work surface, using overlapping strokes with a low-lint wiper so no strip of surface is skipped.

    Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, cleaning and disinfecting the primary engineering controlReport a problem with this question

15. 15. The label of the facility's disinfectant states that treated surfaces must remain visibly wet for a stated period. How must the compounder use it?

    • A.Keep the surface wet for the whole stated period, then let it dry before use.✓ Answer
    • B.Apply the agent twice in a row and begin compounding straight away.
    • C.Wipe the agent away as soon as the surface has been covered evenly.
    • D.Use a larger volume of the agent so the stated period is shortened.

    The wet contact time on the label is the interval the manufacturer validated for the microbial claim, so wiping the agent off early means that claim was never met even though the surface looks clean. Applying more product does not shorten the required interval, and the surface must then be allowed to dry so residue and moisture are not carried into the preparation.

    Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, manufacturer-specified contact time for cleaning and disinfecting agentsReport a problem with this question

16. 16. Which requirement applies to the wipers and cleaning agents used inside the primary engineering control?

    • A.They must be sterile and free of lint when used inside it.✓ Answer
    • B.They must be stored inside the workbench between the shifts.
    • C.They must be rinsed with tap water after each single use.
    • D.They must be woven cotton so that they can absorb more liquid.

    Anything that touches the direct compounding area can deposit whatever it carries onto surfaces that will contact critical sites, so wipers, pads and mop heads used inside the device must be sterile and low-lint, and a concentrate diluted for use there is diluted with sterile water. Woven cotton sheds fibers and tap water is not sterile, so neither belongs inside the device.

    Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, sterile low-lint supplies for cleaning inside the primary engineering controlReport a problem with this question

17. 17. A shipping carton of prefilled syringes arrives for use in the workbench. How should the syringes be introduced?

    • A.Carry the sealed shipping carton in and open it in the workbench.
    • B.Remove them from the carton outside, then disinfect each outer surface.✓ Answer
    • C.Open the carton in the room and stack the syringes near the front edge.
    • D.Set the carton on the work surface so that the airflow decontaminates it.

    Corrugated cardboard sheds fibers, holds dust and cannot be disinfected, so shipping cartons are removed outside the compounding area and never brought into it. Each item is then wiped with sterile alcohol and allowed to dry before it enters the device, and items are arranged with space between them rather than stacked at the open edge, where the airflow is weakest.

    Source: USP General Chapter <797> Pharmaceutical Compounding — Sterile Preparations, introduction and disinfection of supplies entering the compounding areaReport a problem with this question

18. 18. A needle has been used for a transfer and must now be discarded. What is correct practice?

    • A.Bend the needle over so that it cannot be reused, then discard it.
    • B.Place it straight into the sharps container without recapping it by hand.✓ Answer
    • C.Recap it using both hands before dropping it in the sharps container.
    • D.Set it on the work surface until the whole batch has been finished.

    A large share of needlesticks happen during recapping, because two-handed recapping points a contaminated needle straight at the hand holding the cap. Used needles are therefore not recapped, bent, broken or sheared; any safety device is activated and the sharp goes into a puncture-resistant container at the point of use, and if recapping is truly unavoidable a one-handed scoop or a mechanical holder is used.

    Source: OSHA Bloodborne Pathogens Standard, handling and disposal of contaminated sharpsReport a problem with this question

19. 19. An ampule has been snapped open and its contents withdrawn. Where do the glass top and body go?

    • A.Into the general trash once the glass has been rinsed off clean.
    • B.Into the recycling stream that is kept for laboratory glass.
    • C.Into the puncture-resistant sharps container at point of use.✓ Answer
    • D.Into a sealed plastic bag left on the work surface for later.

    A snapped ampule is broken glass with drug residue on it, which makes it a sharp regardless of the fact that no needle was involved. It goes directly into a closable, puncture-resistant, leak-proof container at the point of use, where it cannot cut a housekeeper later, and the container is replaced at its marked fill level rather than pressed down or reached into.

    Source: OSHA Bloodborne Pathogens Standard, sharps containers and disposal of contaminated broken glassReport a problem with this question

20. 20. A technician is stuck by a needle used to compound a non-hazardous preparation. What is done first?

    • A.Wash the wound with soap and water, then report it immediately.✓ Answer
    • B.Finish the batch in progress and report it at the end of the shift.
    • C.Recap the needle carefully and keep it for the investigation file.
    • D.Squeeze the wound to bleed it and cover it with a sterile glove.

    Washing removes contamination at once, and immediate reporting starts the post-exposure evaluation, which is time-sensitive because the medical options available narrow as hours pass. Squeezing the wound is not recommended and recapping repeats the hazard; the event is documented under the facility's exposure control plan, and any preparation the needle touched is discarded rather than released.

    Source: OSHA Bloodborne Pathogens Standard, exposure incident first aid, reporting, and post-exposure evaluationReport a problem with this question

21. 21. A needle and syringe used to compound an antineoplastic preparation are ready for disposal. How are they handled?

    • A.Separated, with the needle in a sharps bin and the barrel in the trash.
    • B.Discarded intact and uncapped into the container designated for chemotherapy waste.✓ Answer
    • C.Discarded into the ordinary biohazard sharps container in the anteroom.
    • D.Rinsed first with sterile water, then placed in the general sharps bin.

    Residual drug left on the device is still hazardous to everyone downstream, so trace-contaminated sharps and materials go into the designated chemotherapy waste stream rather than ordinary sharps or general waste. The assembly is not taken apart, rinsed or recapped, because each of those steps risks spilling or aerosolizing residue, and bulk hazardous waste follows the facility's separate hazardous-waste stream.

    Source: USP General Chapter <800> Hazardous Drugs — Handling in Healthcare Settings, disposal of hazardous drug contaminated materials and sharpsReport a problem with this question

Practice questions based on the PTCB CSPT Content Outline and the USP General Chapters governing sterile compounding. CSPT and PTCB are marks of the Pharmacy Technician Certification Board; this site is not affiliated with or endorsed by PTCB or USP. Standards for sterile compounding are revised periodically and your state board of pharmacy and your employer's policies also apply — always follow your facility's current procedures and confirm current requirements before testing. About the CSPT exam →