Every patient gets Standard Precautions. You layer Transmission-Based Precautions on top whenever the organism spreads in a way hand hygiene and gloves alone can’t stop — Contact (gown + gloves), Droplet (surgical mask within ~3 feet), or Airborne (N95 respirator + a negative-pressure room). Two facts test-writers love to trip you on: C. difficile needs Contact Precautions and soap-and-water handwashing because alcohol gel doesn’t kill the spores. And TB, measles, and varicella all need Airborne Precautions with an N95 and a negative-pressure room.
What are Standard Precautions?
Standard Precautions are the baseline you use with every patient, every time, regardless of diagnosis or suspected infection status. The logic is simple: you can’t always tell who’s colonized or infected, so you treat blood, all body fluids (except sweat), non-intact skin, and mucous membranes as potentially infectious for everyone.
Core Standard Precautions include:
- Hand hygiene before and after every patient contact, before an aseptic task, after body-fluid exposure, and after touching patient surroundings.
- PPE based on anticipated exposure — gloves for contact with body fluids; gown, mask, and eye protection if splashing or spraying is likely.
- Respiratory hygiene / cough etiquette, safe injection practices, and safe handling of contaminated equipment and linens.
- Sharps safety — never recap needles two-handed; activate safety devices and discard in a puncture-resistant container.
Transmission-Based Precautions are added on top of Standard Precautions, never instead of them. If you forget that on an exam, you’ll talk yourself out of the right answer.
The three Transmission-Based Precautions at a glance
The category is determined by how the organism actually travels from one person to another. Contact spreads by touch (direct or via contaminated surfaces). Droplet spreads on large respiratory droplets that fall to the ground within a few feet. Airborne spreads on tiny droplet nuclei that stay suspended in the air and travel on air currents — which is why only this group needs special room ventilation.
| Feature | Contact | Droplet | Airborne |
|---|---|---|---|
| How it spreads | Touch — skin-to-skin or contaminated surfaces/equipment | Large respiratory droplets from coughing, sneezing, talking | Tiny droplet nuclei suspended in air, carried on air currents |
| Key PPE | Gown + gloves | Surgical (procedure) mask | N95 respirator (fit-tested) or PAPR |
| Room | Private room preferred; cohort if needed | Private room preferred; keep ≥3 feet between beds, draw curtain | Airborne Infection Isolation Room — negative pressure, door closed |
| When to mask up | N/A (gown/gloves on room entry) | Mask on room entry / within ~3 feet of patient | N95 donned before entering the room |
Contact Precautions
Put on a gown and gloves before entering the room, and remove them before you leave. The reason you don PPE on entry and doff before exit is environmental contamination — organisms like VRE, C. difficile, norovirus, and RSV survive on surfaces, so you don’t want to carry them out on your sleeve. Dedicate equipment to the patient (stethoscope, BP cuff) when possible, or disinfect shared items between patients.
Droplet Precautions
Wear a surgical mask for close contact, generally donned on room entry. Droplets are heavy and fall to the ground within about 3 feet, so they don’t require special air handling — a private room is preferred but, if cohorting is unavoidable, keep at least 3 feet of spatial separation and draw the privacy curtain. Have the patient wear a surgical mask during transport.
Airborne Precautions
This is the only category that needs special engineering controls. The patient goes in an Airborne Infection Isolation Room (AIIR): negative pressure relative to the hallway, with the door kept closed and air either exhausted directly outside or filtered through a HEPA filter. Per CDC, an AIIR should provide ≥12 air changes per hour for new construction or renovation and ≥6 air changes per hour for existing facilities. Don a fit-tested N95 respirator (or higher) before you enter. If the patient must leave the room, they wear a surgical mask — not an N95 — because the goal is to contain their droplet nuclei.
The master cheat sheet: organism → precaution → PPE → key notes
This is the table to memorize. If you can reproduce it on scratch paper before the exam starts, most infection-control questions become a lookup.
| Disease / Organism | Precaution | Required PPE | Key notes |
|---|---|---|---|
| Clostridioides difficile (C. diff) | Contact | Gown + gloves | Wash hands with soap and water — NOT alcohol gel. Alcohol does not kill spores. Use a bleach-based (sporicidal) disinfectant on surfaces. |
| MRSA (methicillin-resistant S. aureus) | Contact | Gown + gloves | Multidrug-resistant; dedicate equipment to the patient when possible. |
| VRE (vancomycin-resistant Enterococcus) | Contact | Gown + gloves | Survives on surfaces; meticulous environmental cleaning. |
| RSV (respiratory syncytial virus) | Contact | Gown + gloves | Common in infants/young children; spread by hands and contaminated surfaces. |
| Scabies, lice, draining/uncontained wounds, norovirus | Contact | Gown + gloves | Norovirus also needs soap-and-water handwashing; it resists alcohol gel. |
| Pertussis (whooping cough) | Droplet | Surgical mask | Mask on room entry; private room preferred. |
| Influenza | Droplet | Surgical mask | Add gown/gloves if splashing or close contact is likely. |
| Meningococcal meningitis (Neisseria meningitidis) | Droplet | Surgical mask | Droplet precautions for the first 24 hours of effective antibiotic therapy. |
| Mumps, rubella, pharyngeal diphtheria, group A strep (pneumonia/pharyngitis in children) | Droplet | Surgical mask | Same surgical-mask rule as above. |
| Tuberculosis (active pulmonary/laryngeal TB) | Airborne | N95 + negative-pressure room | AIIR, door closed. Patient wears a surgical mask if transported. |
| Measles (rubeola) | Airborne | N95 + negative-pressure room | Highly contagious; per CDC, all staff wear a fit-tested N95 or higher on room entry, even if immune to measles. |
| Varicella (chickenpox) & disseminated zoster | Airborne + Contact | N95 + gown + gloves + negative-pressure room | Skin lesions are infectious, so add Contact to Airborne until lesions crust over. |
| Smallpox (variola) | Airborne + Contact | N95 + gown + gloves + negative-pressure room | Airborne plus Contact regardless of procedure — not AGP-dependent. Continue until all scabs have crusted and separated (about 3–4 weeks). Immune (vaccinated) staff should provide care whenever they are available. |
| SARS (SARS-CoV-1) | Airborne + Droplet + Contact | N95 + eye protection + gown + gloves + negative-pressure room | CDC lists SARS as Airborne plus Droplet plus Contact with eye protection — not AGP-dependent. Continue for the duration of illness plus 10 days after fever resolves, provided respiratory symptoms are absent or improving. An AIIR is preferred; use Droplet Precautions if no AIIR is available. |
| COVID-19 | Airborne + Contact (per facility policy) | N95 + eye protection + gown + gloves | Per current CDC guidance, wear an N95 or higher for patient care — not just for aerosol-generating procedures. Perform aerosol-generating procedures in an AIIR. Follow current facility/CDC guidance. |
Two memory hooks worth the ink:
- “My Chicken Hez TB” → Airborne: Measles, Chickenpox (varicella), Herpes zoster (disseminated), TB.
- Droplet “SPIDERMAN”: Streptococcus (group A — pharyngitis/scarlet fever/invasive disease; not sepsis in general), Pertussis/Parvovirus/Pneumonia (the droplet pneumonias: Mycoplasma pneumoniae, adenovirus, pneumonic plague, group A strep — not all pneumonia), Influenza, Diphtheria, Epiglottitis, Rubella, Mumps/Meningitis (meningococcal/H. influenzae), Adenovirus, Neisseria.
What’s the correct order to put on and take off PPE?
Sequence questions are nearly guaranteed. The guiding principle for doffing is simple: remove the most contaminated items first. Your gloved hands touch everything, so gloves come off first. The respirator (or mask) protects your airway, so it comes off last, removed by its ties or elastics without touching the contaminated front — and for an N95, you remove it after you’ve left the room.
| Step | Donning (putting ON) | Doffing (taking OFF) |
|---|---|---|
| 1 | Gown | Gloves |
| 2 | Mask or respirator | Goggles / face shield |
| 3 | Goggles / face shield | Gown |
| 4 | Gloves (pull over gown cuffs) | Mask or respirator (remove after leaving the room) |
A few details that turn a “good guess” into a sure answer:
- Don gown first so the rest of your PPE overlaps it; pull gloves over the gown cuffs so no wrist is exposed.
- Doff gloves first because they’re the dirtiest, then perform hand hygiene. Many protocols have you perform hand hygiene again between steps and always at the very end.
- Remove the mask/respirator last and outside the room. Handle it by the ties or elastic, never the front, and don’t touch your face.
- Hand hygiene is the bookend — it happens before donning and after doffing every single time.
What is a Protective (neutropenic) Environment?
Don’t confuse Airborne Precautions with a Protective Environment — they’re opposites. Airborne isolation protects others from the patient using negative pressure. A Protective Environment protects the patient from outside organisms using positive pressure. This is for the most immunocompromised patients — classically allogeneic hematopoietic stem cell transplant recipients and severely neutropenic patients.
| Feature | Protective Environment (neutropenic) | Airborne Isolation (AIIR) |
|---|---|---|
| Goal | Keep germs OUT (protect the patient) | Keep germs IN (protect everyone else) |
| Room pressure | Positive relative to the hallway | Negative relative to the hallway |
| Air handling | ≥12 air changes/hour, HEPA-filtered incoming air | ≥12 air changes/hour (new construction) or ≥6 (existing facilities); exhaust outside or HEPA-filtered |
| Other measures | No fresh/dried flowers or potted plants; sealed, scrubbable room | Door kept closed; N95 for staff entering |
For a neutropenic patient, the priority interventions are positive-pressure HEPA-filtered air, strict hand hygiene, and removing standing water, fresh and dried flowers, and potted plants (a source of Aspergillus). Raw fruits and vegetables and undercooked foods are typically restricted as well. If you want a deeper dive on immune function, neutropenia, and infection control, see our immune and infection control review.
Sample NCLEX questions
1. A nurse is caring for a client with Clostridioides difficile infection. Which action is most important to prevent transmission?
- Cleanse hands with alcohol-based hand sanitizer after care
- Wash hands with soap and water after removing gloves
- Place the client in a negative-pressure room
- Wear an N95 respirator when entering the room
Show answer & rationale
Correct answer: B. C. difficile forms spores that alcohol-based sanitizer does not kill, so soap-and-water handwashing is required to mechanically remove them. A is wrong for that same reason — alcohol gel is inadequate against spores. C and D describe Airborne Precautions; C. diff is a Contact (gown + gloves) organism, not airborne.
2. A client is admitted with suspected active pulmonary tuberculosis. Which room and PPE are appropriate? (Select all that apply.)
- ☐ Airborne Infection Isolation Room with negative pressure
- ☐ Fit-tested N95 respirator donned before entering
- ☐ Surgical mask for the nurse on room entry
- ☐ Surgical mask on the client during transport out of the room
- ☐ Keep the room door closed
Show answer & rationale
Correct answers: 1, 2, 4, 5. TB requires Airborne Precautions: a negative-pressure AIIR with the door closed, and a fit-tested N95 donned before entry. The client wears a surgical mask during transport to contain droplet nuclei. Option 3 is wrong — a surgical mask does not protect the nurse from airborne particles; the nurse needs an N95.
3. A nurse has finished caring for a client on Contact and Droplet Precautions. In what order should PPE be removed?
- Gloves, goggles, gown, mask
- Gown, gloves, goggles, mask
- Mask, gown, goggles, gloves
- Goggles, gloves, mask, gown
Show answer & rationale
Correct answer: A. Doff from dirtiest to cleanest: gloves first (most contaminated), then goggles/face shield, then gown, then mask last. The mask protects the airway and is least contaminated, so it comes off last — and outside the room if it’s a respirator. The other sequences leave you handling clean items with contaminated hands.
4. A nurse is assigned a neutropenic client following an allogeneic stem cell transplant. Which intervention is appropriate for a Protective Environment?
- Maintain the room at negative pressure relative to the hallway, door kept closed
- Use positive pressure with HEPA-filtered air; remove fresh flowers and plants
- Require all staff to wear a fit-tested N95 respirator before entering the room
- Restrict the client to soap-and-water hand hygiene only, never alcohol-based rub
Show answer & rationale
Correct answer: B. A Protective Environment keeps organisms away from a vulnerable client using positive pressure and HEPA-filtered air, and removing fresh/dried flowers and potted plants reduces fungal (Aspergillus) exposure. A describes Airborne isolation, the opposite goal. N95s (C) protect staff from the client, which isn’t the point here. D is not a Protective Environment measure.
Frequently Asked Questions
Why can’t I use alcohol-based sanitizer for C. difficile?
C. difficile produces hardy spores that alcohol does not destroy. Soap-and-water handwashing physically washes the spores off your hands, and surfaces should be cleaned with a sporicidal (bleach-based) disinfectant. The same handwashing rule applies to norovirus.
What’s the difference between a surgical mask and an N95?
A surgical mask blocks large respiratory droplets and is used for Droplet Precautions. An N95 respirator filters tiny airborne particles and must be fit-tested; it’s required for Airborne Precautions (TB, measles, varicella). A surgical mask will not protect you from airborne organisms.
Why do some patients need both Airborne and Contact Precautions?
When an organism spreads by more than one route, you combine precautions. Varicella (chickenpox) and disseminated herpes zoster travel through the air and through contact with infectious skin lesions, so the patient needs an N95, a negative-pressure room, and gown plus gloves until the lesions crust over.
Is negative pressure the same as a Protective Environment?
No — they’re opposites. Negative pressure (Airborne isolation) pulls air into the room so contaminated air doesn’t escape, protecting others. A Protective Environment uses positive pressure to push filtered air out, keeping germs away from an immunocompromised patient.
Do Transmission-Based Precautions replace Standard Precautions?
Never. Standard Precautions apply to every patient at all times. Contact, Droplet, and Airborne Precautions are layered on top when the route of transmission requires it.
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- CDC Isolation Precautions Guideline: Recommendations — Standard scope; droplet mask/3 ft; AIIR 6/12 ACH, negative pressure; N95; PE HEPA, +pressure, no plants
- CDC Isolation Precautions Appendix A: Type and Duration of Precautions — Precaution type and duration per disease (C. diff, TB, varicella, smallpox, SARS, pertussis, etc.)
- CDC Sequence for Putting On and Removing PPE — Donning gown-mask-goggles-gloves; doffing gloves-goggles-gown-mask; respirator removed outside room
- CDC Interim Infection Prevention and Control Recommendations for Measles — Measles: AIIR placement; N95 for all staff regardless of immunity
- CDC Standard Precautions for All Patient Care — Standard Precautions elements: hand hygiene, PPE, cough etiquette, safe injection
Sources checked September 2026.