FAQ about disinfectants: 15 frequently asked questions from hospital and clinic managers

Correct disinfectant management directly influences patient safety, staff protection, and the facility's legal compliance. As a manager, you select the products, establish the protocols, and are responsible for how they are implemented. Any wrong decision at this level (an unauthorized product, incorrect dilution, or failure to respect contact time) can generate healthcare-associated infections (HAIs), DSP (Public Health Directorate) sanctions, or, in extreme situations, civil liability.

Read this article and discover 15 questions and answers from hospital and clinic managers!

1. What types of disinfectants are used in hospitals and clinics?

The classification of medical disinfectants is based on two main criteria: the level of disinfection and the active substance.

By level of disinfection (according to Ministry of Health Order no. 1761/2021 and EN standards):

• Low level: bactericidal (vegetative bacteria), yeasticidal, and virucidal activity against enveloped viruses. Used on non-critical, low-risk surfaces (administrative offices, areas without direct patient contact). Does not cover mycobacteria, non-enveloped viruses, or spores.
• Intermediate level: includes mycobactericidal/tuberculocidal activity (tested according to EN 14348 and EN 14563) and virucidal activity against non-enveloped viruses (according to EN 14476, EN 16777, and EN 17111). Suitable for surfaces that come into contact with intact skin and for non-critical instruments with intermediate risk.
• High-level (HLD): bactericidal (EN 13727, EN 17387, EN 14561), fungicidal (EN 13624, EN 17387, EN 14562), mycobactericidal (EN 14348, EN 14563), virucidal (EN 14476, EN 16777, EN 17111), and, under certain conditions, sporicidal (EN 17126) activity. Mandatory for semi-critical instruments (endoscopes, transvaginal ultrasound probes, laryngoscopes).

By active substance:

• Alcohols (ethanol 70–85%, isopropanol): rapid action through protein denaturation and destruction of cell membranes; not sporicidal; no residual activity.
• Quaternary ammonium compounds (QAC): destabilize the bacterial membrane; can be inactivated by organic matter; do not cover spores.
• Hydrogen peroxide: generates free radicals that oxidize cellular structures; at concentrations ≥6% it can be sporicidal; decomposes into water and oxygen.
• Sodium hypochlorite: rapid oxidation, indicated for outbreaks of Clostridioides difficile; prepare the solution daily (activity is lost in 24–48 hours); corrodes stainless steel and aluminum.
• Synergistic combinations (amides, amines, QAC, peroxide, alcohols): broad spectrum, documented activity across multiple categories.

All disinfectants used in the medical environment must be authorized as biocidal products by the Ministry of Health and registered in the National Register of Biocidal Products, according to Emergency Ordinance no. 41/2019 and Regulation (EU) no. 528/2012. Learn more about active ingredients in biocidal products: alcohols, phenols, aldehydes!

2. How do you choose the right disinfectant for each area in the hospital or clinic?

Do not apply the same solution everywhere. Choosing the correct product starts with evaluating three factors: the epidemiological risk of the area, the type of surface or device, and material compatibility.

Risk stratification (according to Ministry of Health Order no. 1761/2021):

• High risk (operating room, ICU, delivery rooms, sampling room, dental offices): high or intermediate-high level products, validated against mycobacteria and non-enveloped viruses; disinfection after each patient/procedure or at least twice daily.
• Medium risk (patient wards, consultation rooms without invasive procedures, bathrooms): intermediate-level products; disinfection at least once a day and whenever necessary.
• Low risk (administrative offices, hallways, storage rooms): low-level products; periodic cleaning according to the internal plan.

Material compatibility is a frequently neglected technical criterion:

• Sodium hypochlorite corrodes stainless steel and aluminum; do not use it on metal instruments or surfaces made of sensitive alloys.
• Alcohol can affect lacquered surfaces, certain plastics, and electronic equipment screens.
• Hydrogen peroxide can bleach some textiles and may affect certain metals at high concentrations.

Always consult the medical equipment manufacturer's recommendations before applying a new disinfectant to its surfaces.

3. What is the operational difference between cleaning, disinfection, and sterilization?

Each defines a distinct intervention, with its own function and limits.

Cleaning mechanically removes visible dirt, dust, and organic matter through the action of a detergent and mechanical force. It does not destroy microorganisms, but it reduces their number and, essentially, removes organic matter that would inactivate disinfectants. Cleaning is the mandatory stage before any disinfection or sterilization. A disinfectant applied to blood or secretions is partially or totally inactivated.

Disinfection reduces the number of pathogenic microorganisms to a level that no longer poses a risk to patients or staff. Efficiency depends on three controllable factors: product concentration, contact time, and application temperature. Disinfection does not destroy bacterial spores in large numbers.

Sterilization destroys all forms of microbial life, including the most resistant bacterial spores. It is the only acceptable method for critical instruments that penetrate sterile tissues. It is achieved via: pressurized steam autoclave (134°C, 3–5 minutes or 121°C, 15 minutes, in class B autoclaves), hydrogen peroxide plasma, or ethylene oxide for thermosensitive devices.

Basic rule: cleaning does not disinfect, disinfection does not sterilize. The three processes are applied in order and do not replace each other.

4. What does "high-level disinfectant" mean and when is it mandatory?

A high-level disinfectant (HLD) destroys all microorganisms, including mycobacteria, non-enveloped viruses, fungi, and, under certain concentration and time conditions, bacterial spores. It is the reference product for reprocessing semi-critical instruments.

Mandatory use (according to Ministry of Health Order no. 1761/2021 and the Spaulding classification):

• flexible and rigid endoscopes (bronchoscopes, gastroscopes, colonoscopes, cystoscopes);
• transvaginal and transrectal ultrasound probes;
• laryngoscopes and reusable laryngoscope blades;
• reusable vaginal specula;
• accessories for procedures involving mucosal contact.

Klintensiv products for high-level disinfection:

• Dezicon (concentrate): documented sporicidal efficacy (EN 17126); prepared in an opaque plastic tub, labeled with name, concentration, and date and time of preparation.
• Peroklin (ready-to-use): high level, no dilution required.
• Sterisol RTU (ready-to-use): high level, for rapid use without the risk of dilution errors.

5. What active substances are frequently used in disinfectants and how do they act?

• Ethyl alcohol (ethanol) 70–85% denatures proteins and destroys bacterial and viral cell membranes. Rapid action (30 seconds–2 minutes), no residual activity. Not sporicidal. Not used in the presence of visible organic matter. An active ingredient found in both TP1 products for hands and skin, and TP2 products for medical surfaces and instruments.
• Quaternary ammonium compounds (QAC) destabilize the bacterial cell membrane and inactivate enveloped viruses. Good residual activity. Can be inactivated by organic matter, hard water, and anionics (detergents). Not effective against mycobacteria or spores in monotherapy. Useful in synergistic combinations with alcohols or other agents.
• Hydrogen peroxide generates free radicals that oxidize cellular proteins, lipids, and nucleic acids. At concentrations ≥6% it can be sporicidal, or may have this efficacy at lower concentrations when combined with other active ingredients. Decomposes into water and oxygen. At high concentrations, it can corrode certain metals and bleach textile surfaces.
• Sodium hypochlorite rapidly oxidizes cellular components. Effective against Clostridioides difficile (a situation where alcohol does not work, as spores are not inactivated by alcohols). Prepare the solution daily, as activity decreases significantly within 24–48 hours. Corrodes stainless steel and aluminum; avoid use on metal instruments.
• Glutaraldehyde (2%): Toxic if inhaled; requires forced ventilation and rigorous protective equipment. Use is declining in favor of safer formulas for staff.

6. What is used for disinfecting skin and wounds?

Skin and mucous membranes require disinfectants for hands and skin, not surface disinfectants. Using a surface disinfectant on skin can cause chemical irritation, burns, or sensitization.

Intact skin (surgical field, sampling, injections):

• Alcoholic solutions above 80% (application by wiping);
• Alcoholic chlorhexidine 0.5–2% (longer residual action, recommended before invasive procedures);
• Povidone-iodine 7.5% (broad spectrum; allow to dry before the procedure). An example is Betaklin.

Always verify the product's intended use in the biocidal authorization.

Klintensiv products for hand hygiene:

• Alchosept / Klintensiv Hand Disinfectant Gel: hygienic disinfection by rubbing (3 ml, 30 seconds), surgical disinfection (3 ml, 90 seconds);
• CHDG Soap: hygienic disinfecting liquid soap (3 ml, 1 minute) and surgical (2×4 ml, 2×2 minutes);
• Klinsafe: mild liquid soap without SLES, for frequent washing (3 ml, 30 seconds).

7. What is contact time and why is it critical for compliance?

Contact time is the period during which the surface must remain wet with the disinfectant product to achieve the microbiological efficacy declared in the technical data sheet and proven by EN tests.

A product may achieve bactericidal activity in 1 minute, but virucidal activity according to EN 14476 in 5 minutes and mycobactericidal activity according to EN 14348 in 60 minutes. If the surface is wiped after 30 seconds, the full declared spectrum is not reached.

Practical implications:

• The amount of product applied must be sufficient to keep the surface wet throughout the contact time; if it dries prematurely, reapply.
• For large surfaces or products with long times, the spray-and-wipe method (wiping after the time expires) is more effective than immediate wiping.
• Explicitly instruct staff regarding contact times; this is the most common type of error in protocol implementation.

8. How is nebulization disinfection performed and when is it indicated?

Nebulization (fogging) disperses a disinfectant in the form of fine particles into the air of a space, treating surfaces and the air simultaneously. It does not replace mechanical surface cleaning; organic matter and visible dirt also block biocidal action during nebulization.

Recommended product: Desogen Aero, high-level disinfectant for nebulization, ready-to-use, 10 ml/m³, contact time 30 minutes.

Mandatory protocol:

• The space must be completely evacuated (patients and staff) before nebulization.
• Doors and windows must be closed during treatment.
• Mechanical ventilation must be turned off to prevent dispersion into other areas.
• Re-entry is allowed only after complete airing and the expiration of the safety time indicated in the product's technical data sheet.
• Mandatory documentation: date, time, person responsible, product used, space treated, concentration, and dose applied.

9. How do you prevent microbial resistance to disinfectants?

Microbial resistance to biocides is a real risk, documented in specialized literature, associated with the repeated subinhibitory use of the same active substances. Mechanisms include active efflux, outer membrane modifications, and the selection of resistant mutants, with potential co-resistance to antibiotics.

Prevention measures:

• Respect correct concentrations — a concentration below the recommended one creates selection pressure without ensuring complete biocidal efficacy; conversely, a concentration that is too high does not increase antimicrobial performance, but can generate toxicity, waste, and corrosion.
• Periodic rotation of active substances — especially in high-risk areas (ICU, operating room, oncology wards); alternate classes of active substances according to a documented plan.
• Do not dilute arbitrarily — implement controlled dosing systems (unit doses, automatic dosing and dilution systems) to eliminate human variability.
• Microbiological monitoring — perform surface swabs periodically and after outbreaks; if the laboratory identifies persistent strains, review the product and protocol.
• Do not leave the product in prolonged contact with surfaces without rinsing, unless instructions state otherwise — residues can exert continuous selection pressure at subinhibitory concentrations.

10. What documents must a disinfectant have to be used legally?

Using a disinfectant without complete and valid documentation constitutes a legal non-compliance detectable during DSP inspections. Always verify:

Mandatory documents per product:

• Biocidal product authorization issued by the Ministry of Health, with a registration number in the National Register of Biocidal Products, proving the product is authorized for sale and use in Romania, according to Emergency Ordinance no. 41/2019 and Government Decision no. 617/2014.
• Compliance with Regulation (EU) no. 528/2012 regarding biocidal products — for products imported from the EU or marketed on the European market.
• Efficacy test results according to relevant EN standards — documented in the technical data sheet, test reports, or declaration of performance; verify that the tests cover the spectrum declared on the label (bactericidal, virucidal, mycobactericidal, etc.).
• Updated Safety Data Sheet (SDS/MSDS) — mandatory according to Regulation (EC) no. 1907/2006 (REACH); contains information regarding handling, storage, protective equipment, and emergency procedures.
• Clear instructions for use regarding working concentration, dilution methods, contact times, application conditions, and shelf life of the prepared solution.

11. What is the difference between concentrated and ready-to-use (RTU) products?

Do not use concentrates in units without written dilution procedures and without controlled dosing systems. Incorrect preparation of the working solution — either through under-concentration (which cancels biocidal efficacy) or over-concentration (which increases the risk of toxicity and corrosion) — compromises the entire safety protocol. For wards with high consumption and trained staff, concentrates significantly reduce the cost per dose and the volume of plastic generated.

12. Which surfaces must be disinfected mandatorily and with what frequency?

"High-touch" surfaces require disinfection after each patient or procedure:

• door handles (interior and exterior of all rooms with patient access);
• bed rails and handles;
• medical equipment buttons (infusion pumps, monitors, ventilators);
• protected keyboards and physician work surfaces;
• examination/treatment tables and stretchers;
• faucets and sink taps;
• elevator handles (in hospitals).

Medium-risk surfaces require at least daily disinfection:

• door handles in administrative and waiting areas: at least 3 times/day;
• furniture in waiting rooms;
• sanitary facility surfaces: at least 2 times/day.

Low-touch surfaces must be disinfected according to the internal plan (weekly or as needed):

• walls, ceilings, blinds, ventilation networks.

Terminal disinfection — mandatory when changing a patient in a room, upon discharge, and at the end of the operating schedule: complete treatment of all surfaces, including low-touch ones.

13. How do you establish and document the frequency of disinfection in the unit?

The optimal frequency is established by assessing the epidemiological risk of each area, not by estimation. The legal basis is MS Order no. 1761/2021.

Practical method:

• Area mapping — classification into high, medium, and low-risk zones on a unit diagram.
• Establishing frequency per zone — correlated with the identified risk and patient flow.
• Written procedures — one standard operating procedure (SOP) per type of intervention (routine disinfection, terminal, in case of an epidemic, etc.).
• Cleaning/disinfection chart — mandatory to be filled out in real-time (not retrospectively); includes: surface, time of intervention, product, concentration, person responsible.
• Periodic internal audit — verification of protocol compliance against written documents; microbiological surface swab for validation.

Minimum reference frequencies:

• Operating block, ICU: after every procedure and terminal disinfection at the end of the operating list.
• Patient rooms: 2–3 times/day and terminal disinfection upon patient discharge.
• Consultation offices: after every patient for direct-contact surfaces.
• Administrative offices: once a day, with a focus on high-touch areas.

Also read this guide on disinfection in healthcare units!

14. How do you optimize disinfectant costs without reducing safety?

Optimizing costs with biocides is not done by reducing frequency or by using stronger dilution of products — both increase the risk of HAI, with exponentially higher treatment costs. Real optimization happens at the level of selection and efficient use.

Effective strategies:

• Calculate the cost per applied dose, not the price per liter of product. A 2% concentrate with a 60-minute contact time can cost 3–5 times less per dose than an equivalent RTU, but it requires trained personnel and dosing systems.
• Eliminate portfolio overlaps. If you have 4 products covering the same spectrum for the same application, some are redundant. A biocide portfolio audit identifies products that can be consolidated without loss of coverage.
• Implement controlled dosing systems.
• Standardize products across wards with similar risk.
• Monitor monthly consumption per ward and compare with estimated standards. Large deviations (excessive or under-reported consumption) signal either waste or failure to apply the protocol.
• Evaluate the ROI of training; correctly trained staff use products according to instructions, reduce rework, and minimize contamination incidents.

15. What are the most frequent mistakes and how do you correct them systemically?

Mistake 1: Disinfection applied to uncleaned surfaces

Cause: urgency or incomplete procedures.

Consequence: the disinfectant is inactivated by organic matter.

Correction: specific training + visible checklist at every workstation.

Mistake 2: Failure to observe contact time

Cause: time pressure between patients, lack of knowledge.

Consequence: the declared microbiological spectrum is not reached.

Correction: written protocols with explicit times, periodic training, supervision.

Mistake 3 — Incorrect concentrate dilutions

Cause: lack of dosing systems, insufficient training.

Consequence: under-concentration (inefficiency) or over-concentration (toxicity, corrosion, waste).

Correction: automatic dosing systems or dedicated graduated syringes, preparation sheets posted at the preparation site.

The 15 questions above cover the decision-making area of any manager responsible for the biological safety of a medical unit. Review existing protocols, check product approvals, standardize dilutions, and document every intervention.