Personal Protective Equipment (PPE) in the Laboratory: Types, Selection, Donning, and Doffing

In 2004, a laboratory technician in a clinical microbiology laboratory was centrifuging a specimen tube when it cracked inside the centrifuge. An aerosol of potentially infectious material was generated. The technician had not been wearing eye protection — a decision that seemed reasonable at the time, since the procedure was routine. The resulting eye contamination required post-exposure evaluation and a course of prophylactic therapy.

PPE does not feel necessary until the moment it is needed — and at that moment, there is no time to put it on. Laboratory accidents follow a predictable pattern: routine procedures, familiar equipment, a momentary lapse in protective measures. The purpose of PPE is not to respond to emergencies but to ensure that when an unexpected exposure occurs, the route of transmission is already blocked.

For microbiology laboratory staff, infection control teams, and clinical personnel, understanding which PPE to use, in which combination, for which specific hazard — and how to put it on and take it off without self-contaminating — is as fundamental as knowing how to use a pipette.

Personal Protective Equipment (PPE) is the safety clothing and devices worn to ensure safety to various occupational risks. It can be caused by exposure to chemicals, mechanicals, radiological or electrical hazards. Medical personnel wears them to be safe from exposure to transmissible diseases and prevent injuries. Doctors, nurses, laboratory technicians, and other front-line health personnel wear PPE in their workstations. The type of the PPE may differ on the nature of the work and the levels of the hazards. Examples of personal protective equipment in the laboratory include laboratory coats, safety glasses or splash goggles, gloves, etc.

Before using personal protective equipment, one needs to be fully aware of the laboratory protocols. The laboratory personnel should avoid short dress, loose clothing, ornaments, open hair, and open-toe shoes. The appropriate protocol needs to be followed while donning (putting on) PPE and doffing (taking off) PPE.

Types of the Personal Protective Equipment(PPE)

Personal protective equipment is of various types. It includes protecting the body, face, eyes, hearing, and respiratory protection.

Figure: Personal Protective Equipment (PPE) in the laboratory

Body protection

Lab coats

It protects the laboratory personnel’s clothes and skin from any stains of the dyes, blood, or any other dust, dirt, or laboratory contaminants. A lab coat is also a semi-fire retardant. 35 % polyester and 65% cotton are used in the ideal lab coat. Cotton has the property of semi-fire retardant, whereas polyester possesses resistance to chemicals. When the lab coat is kept in the laboratory only, it minimizes the risk of cross-contamination to the other surface areas and minimizes its hazard. Chemical resistant sleeves and aprons can be used based on the hazard and potential risk assessment.

Aprons

An apron is used when any additional hazard-specific splash protection is required. It is used in the process of removing liquid nitrogen. An apron is used when a large volume of the fluid sample is to be handled or when handling chemicals. In the laboratory, an apron is also used during the autopsy.

Gowns

The gown provides coverage like that of laboratory coats; solid-front and has back-closing garments with elasticized cuffs. One can wear it on top of the scrub or top of their clothing. Both the disposable gown and wraparound gowns are available.

Coveralls

Coverall is worn on the top of personal clothing or top of scrubs. They are of both disposable and reusable types. During its removal, it needs to be removed safely. Coveralls with a zip flap should be considered for protection against splashes.

Footwear

Footwear should cover the top of the foot, and it should be well-fitting and comfortable. It must be of a design that prevents the slips and the trips and helps prevent injury from falling objects.

Eye and Face protection

Safety glasses and goggles

Safety glasses are one of the minimum requirements for working in labs around hazardous material. It protects from any flying objects too. It does not protect against the chemical splash. Since the regular safety glass cannot protect against UV rays and lasers, special safety glasses are used.

Face Shields

If there is a chance of the splash hazards, personnel can use face shields in addition to the safety glasses goggles. Possible splash hazards may be during working with a large volume of the liquid, dispensing cryogenics, preparing the corrosive bath, or working with the molten metals.

Respiratory Protection

When there is an inhalation hazard of the harmful gases or which can cause irritants, respiratory protection is required.

Surgical Mask vs N95 Respirator — Understanding the Difference

The COVID-19 pandemic brought widespread awareness of masks and respirators but also significant confusion about when each is appropriate. For laboratory and clinical settings, the distinction is important:

When to use N95 in clinical microbiology: N95 (or equivalent FFP2/FFP3) should be used when: (1) processing sputum for TB culture or smear — sputum induction and processing generate aerosols of potentially viable M. tuberculosis; (2) opening centrifuge tubes after spinning respiratory specimens; (3) vortexing or sonicating specimens; (4) any procedure generating aerosols from a specimen of unknown infectious status in an inadequately ventilated area.

Surgical mask is not respiratory protection. This was clearly established before COVID-19 but bears repeating: a surgical mask does not protect the wearer against airborne particles. It protects against droplets (>5 µm) and prevents the wearer from contaminating the environment. For inhalation protection against aerosols, only a properly fit-tested N95 or powered air-purifying respirator (PAPR) provides adequate protection.

Hand Protection

Gloves

Gloves protect the laboratory personnel’s hands from the risk of exposure to the various contagious laboratory samples. It minimizes the hazards of chemicals. The most commonly used material for the gloves is nitrile, latex, and vinyl. For the laboratory, the minimum protective glove is the disposable nitrile gloves. Such gloves need to be removed immediately when in contact with the chemicals. Disposable gloves should not be reused and should not be disinfected because the exposure of such gloves to the disinfectants and the prolonged use may reduce their protection to the user. Before wearing the glove, it should be checked if it’s torn or intact.

Reusable gloves need to be washed thoroughly and air-dried before using them. The selection of gloves depends upon the purpose and nature of the work. For example, insulated gloves can prevent excess heat, and cut-resistant gloves need to be used to avoid cuts and abrasions.

Glove Material Selection Guide

Not all gloves provide equal protection against all hazards. The choice of glove material should be matched to the specific chemical or biological risk:

Breakthrough time matters: Every chemical glove material has a breakthrough time — the duration before the chemical permeates through the glove to the skin. For extended work with organic solvents, check the glove manufacturer's chemical resistance chart for the specific chemical and select a glove with breakthrough time exceeding your expected exposure duration. Nitrile gloves, for example, have a breakthrough time of minutes for acetone at high concentrations.

Double gloving: For high-risk biological work (BSL-3, known HIV/HBV-positive specimens, suspected haemorrhagic fever), double gloving provides a backup layer if the outer glove is torn. The outer glove should be changed between patients; the inner glove provides a second barrier during the change.

Hearing Protection

If the laboratory personnel is exposed to excessive noise or ultrasound (high frequency), it may cause hearing loss. Ear plugs and ear muffs help in protecting the ear.

Ear plugs

It reduce the amount of noise that reaches the ear via the route of the ear canal. When placed correctly, it expands to fill the ear canal, and the wall in it gets sealed. Both the disposable and the reusable earplugs are available.

Ear muffs

Ear muffs enclose the whole external ears and fit against the head. Its inside part is lined with acoustic foam. Use of the ear muffs with the ear plugs prevents the loud noise.

PPE Selection by Biosafety Level

The combination of PPE required depends on the biosafety level (BSL) of the work being performed, not simply on personal preference or habit. WHO and CDC define minimum PPE requirements for each biosafety level:

For most clinical microbiology laboratories (BSL-2): The standard minimum is lab coat + gloves + eye protection. When performing aerosol-generating procedures (vortexing, pipetting, centrifuging, opening culture tubes), add a surgical mask or N95 depending on the organisms being handled. Work in a biosafety cabinet whenever open manipulation of specimens or cultures is required.

Choosing PPE for Specific Hazards

Different hazards require different protective equipment. The table below maps common laboratory hazards to the appropriate PPE:

Key principle — layered protection: PPE items are not mutually exclusive. A splash of concentrated acid requires goggles (not just safety glasses), chemical-resistant gloves (not nitrile), a chemical apron (not just a lab coat), and proximity to an eyewash station. Assess the hazard, then select the combination that covers all exposure routes for that specific risk.

How to Put On PPE (Donning)

The correct donning sequence ensures that each layer of PPE is applied without contaminating the next item. Two sequences are presented: the standard laboratory sequence for routine BSL-2 work, and the enhanced sequence for high-risk or BSL-3 work.

Standard Laboratory Donning Sequence (BSL-2 Routine Work)

1. Wash hands or use alcohol-based hand sanitiser before touching any PPE
2. Put on lab coat — fasten all buttons/snaps; ensure cuffs cover wrists
3. Put on N95 or surgical mask if aerosol-generating procedure or mask required by protocol
4. Put on eye protection (safety glasses or goggles) — ensure secure fit
5. Put on gloves — pull cuffs over lab coat cuffs
6. Perform a final visual check before beginning work

Enhanced Donning Sequence (High-Risk / BSL-3 / Suspected VHF)

(A trained observer should supervise donning and doffing for all high-risk work)

1. Perform hand hygiene
2. Put on scrubs (inner clothing layer)
3. Put on rubber boots or closed, fluid-resistant shoes + overshoes
4. Put on impermeable gown or solid-front coverall over scrubs; ensure wrist coverage
5. Put on N95 respirator or PAPR — perform seal check
6. Put on goggles
7. Put on face shield over goggles
8. Put on head cover
9. Perform hand hygiene
10. Put on inner gloves (first pair)
11. Put on outer gloves over gown cuffs
12. Observer performs final check — no skin exposed; no gaps between PPE items

During work: Avoid touching or adjusting PPE with gloved hands. If a glove tears, move away from the work area, remove the torn glove, perform hand hygiene, and put on a fresh glove before returning. Change outer gloves between patients.

How to take off Personal Protective Equipment (doffing PPE)?

The Critical Principle: Dirty-to-Clean, Outside-to-Inside

Doffing is the highest-risk step in PPE use. Most PPE-associated contamination events occur during removal, not during use. The governing principle is:

Remove the most contaminated item first, touch only the inside (uncontaminated surface) of each item, and perform hand hygiene between every step.

The outside surface of every PPE item is considered contaminated. Never touch the outside of your mask, the outside of your goggles, or the outer surface of your gown during removal. The gloves — the most contaminated item — come off first, using the inside-out technique that ensures your clean skin never touches the contaminated outer surface.

Standard Laboratory Doffing Sequence (BSL-2)

1. Gloves first — peel off using inside-out technique (see detailed glove removal below); discard into biohazard waste
2. Perform hand hygiene immediately after glove removal
3. Eye protection — remove from behind by the frame/headband; do not touch the front lens surface; place in designated container for reprocessing or discard
4. Gown or lab coat — unfasten; roll away from body touching only inside surfaces; fold contaminated side inward; discard in biohazard waste (disposable) or place in designated laundry container
5. Mask — grasp ties/elastic from behind; do not touch the front; discard into waste
6. Perform hand hygiene — final step

There are various methods for the safe removal of personal protective equipment. Safe practices ensure that the cloth, skin, or mucous membranes don’t get contaminated. Except for the respirator, remove all the PPE before exiting the patient’s room. Remove the respirator after leaving the patient’s room and closing its door.

The outside of the PPE items is contaminated. If, during its removal, hands get contaminated, then wash the hands or use the alcohol-based sanitizer.

Removal of Gloves

1. Firstly, peel one glove by grasping it with the other gloved hand starting from the side of the palm.
2. Then, hold the glove with the gloved hand, slide the ungloved hand’s fingers under the remaining glove at its wrist, and peel off the second glove over the first glove.
3. Finally, discard in the waste container.

Enhanced Doffing Sequence (High-Risk / BSL-3)

A trained observer must supervise doffing for all high-risk work, calling out each step and checking for self-contamination.

Sequence: outer gloves → gown/coverall (roll inward) → hand hygiene → face shield → goggles → N95 (grasp from behind; do not touch front) → hand hygiene → head cover → inner gloves → hand hygiene → move to clean area → remove boots → final hand hygiene

The respirator comes off last and outside the patient room or work area. Removing the N95 inside the contaminated work area exposes the face to residual aerosols. Step out, close the door, then remove the respirator.

Limitations of PPE — What It Cannot Do

PPE is the last line of defence in the hierarchy of controls — it should be used after engineering controls (biosafety cabinets, fume hoods, enclosed systems) and administrative controls (procedures, training, work organisation) have been implemented. PPE has real limitations that every laboratory worker should understand:

Hierarchy of controls — PPE is last resort:

PPE does not reduce the hazard — it only reduces exposure to an unchanged hazard. Engineering controls that contain or eliminate the hazard are always more reliable than PPE that depends on human behaviour.

Disposal of Used PPE

Contaminated PPE is infectious waste and must be disposed of according to laboratory waste management protocols — not in general waste bins.

Reusable PPE must be decontaminated before leaving the laboratory. A lab coat taken home for washing is a route of community exposure. Reusable PPE that is contaminated during high-risk work must be autoclaved or chemically decontaminated before removal from the laboratory.

→ For full laboratory waste disposal protocols, see Hospital and Laboratory Waste Management

How to Remember

PPE works in layers — each layer covers a different route of exposure:

• Body (lab coat, gown) — protects against splash and contact contamination
• Hands (gloves) — protects against the most common route (hand-to-mucous membrane)
• Eyes/face (glasses, goggles, shield) — protects against splash to the most vulnerable mucous membranes
• Respiratory (mask, N95) — protects against inhaled aerosols and droplets

Each layer is independent. Wearing gloves does not protect your eyes. Wearing a mask does not protect your hands. A complete risk assessment asks: what is the exposure route for this hazard, and is that route covered?

The donning-doffing asymmetry: Donning (putting on) = clean to dirty = any order within the sequence is relatively low risk. Doffing (taking off) = dirty to clean = sequence is critical. Always: most contaminated off first; hands cleaned between each item; respirator last outside the room.

The N95 memory rule: Surgical mask = droplet defence (large particles, splash). N95 = aerosol defence (small particles, sustained airborne exposure). If you are generating aerosols from a respiratory specimen, you need an N95, not a surgical mask.

Three questions before starting any laboratory procedure:

1. What is the hazard? (biological, chemical, physical)
2. What is the exposure route? (splash, aerosol, contact, inhalation)
3. Is the PPE I have on protecting that route for this specific hazard?

References

1. World Health Organization. (2020). Rational Use of Personal Protective Equipment for Coronavirus Disease (COVID-19) and Considerations During Severe Shortages. Geneva: WHO. https://www.who.int/publications/i/item/rational-use-of-personal-protective-equipment-for-coronavirus-disease-(covid-19)-and-considerations-during-severe-shortages
2. Centers for Disease Control and Prevention. (2019). Laboratory Biosafety Level Criteria. In Biosafety in Microbiological and Biomedical Laboratories (BMBL), 6th Edition. CDC. https://www.cdc.gov/labs/BMBL.html
3. World Health Organization. (2004). Laboratory Biosafety Manual (3rd ed.). Geneva: WHO. https://www.who.int/publications/i/item/9241546506
4. National Institute for Occupational Safety and Health (NIOSH). (2023). NIOSH-Approved Respirators. CDC/NIOSH. https://www.cdc.gov/niosh/npptl/resprators/
5. Tille, P. M. (2017). Bailey and Scott's Diagnostic Microbiology (14th ed.). Elsevier. [Chapter on Laboratory Safety]