CDC Standard Precautions & Hand Hygiene
Key Takeaways
Standard Precautions apply to all patients regardless of known infection status.
Perform hand hygiene before clean tasks and after patient contact or glove removal; gloves do not replace it.
Alcohol rub is preferred in most clinical situations; wash visibly soiled hands and follow outbreak-specific C. difficile policy.
Use safety-engineered sharps and a suitable container at the point of use; avoid recapping unless a permitted exception applies.
CDC Standard Precautions & Hand Hygiene
In the magnetic resonance imaging environment, infection control is a foundational patient safety competency. The Imaging Assistant (IA) frequently participates in patient transfers, coil positioning, intravenous line preparations, and surface disinfection. Because patients undergoing MRI examinations range from healthy outpatients to critically ill intensive care patients carrying multi-drug resistant pathogens, strict adherence to standardized biological barrier controls is mandatory.
Foundations of CDC Standard Precautions
The Centers for Disease Control and Prevention (CDC) established Standard Precautions as the primary tier of infection prevention across all healthcare delivery settings. Standard Precautions synthesize the concepts of Universal Precautions (aimed at bloodborne pathogens) and Body Substance Isolation into a single, comprehensive standard.
The Universal Principle of Infectivity
Under Standard Precautions, healthcare personnel must treat all human blood, bodily fluids, secretions, excretions, non-intact skin, and mucous membranes as potentially infectious for transmissible pathogens (including Human Immunodeficiency Virus [HIV], Hepatitis B Virus [HBV], and Hepatitis C Virus [HCV]), regardless of whether a patient exhibits symptoms of infection or has a documented diagnosis.
| Substance Category | Clinical Status Under Standard Precautions | Examples and Special Considerations |
|---|---|---|
| Blood & Blood Components | High-risk infectious source | Whole blood, plasma, serum, packed red blood cells |
| Potentially Infectious Body Fluids | Covered under Standard Precautions | Cerebrospinal fluid (CSF), synovial fluid, pleural fluid, peritoneal fluid, pericardial fluid, amniotic fluid |
| Excretions & Secretions | Covered under Standard Precautions | Saliva, sputum, nasal secretions, tears, urine, feces, emesis, semen, vaginal secretions |
| Non-Intact Skin & Mucosa | Covered under Standard Precautions | Open surgical wounds, abrasions, decubitus ulcers, oral mucosa, conjunctiva |
| Sweat | The Sole Explicit Exemption | Excluded from Standard Precautions unless visibly contaminated with blood |
Note
The explicit exclusion of uncontaminated sweat is a frequent ARRT exam point. However, because perspiration on coil cushions frequently mixes with microscopic skin shedding or non-intact epidermal surfaces, environmental cleaning of all contact surfaces remains obligatory.
Hand Hygiene Guidelines & Clinical Execution
Hand hygiene is universally recognized as the single most effective intervention for preventing healthcare-associated infections (HAIs). Pathogenic micro-organisms are predominantly transferred between patients via the contaminated hands of healthcare personnel.
The WHO / CDC 5 Moments for Hand Hygiene
The World Health Organization (WHO) and CDC define five distinct clinical indications when hand hygiene must occur during patient care workflows:
- Before Touching a Patient: Prior to greeting the patient, assisting them from a wheelchair, or initiating clinical contact.
- Before a Clean or Aseptic Procedure: Immediately before palpating an intravenous injection site, assembling sterile contrast delivery lines, or handling sterile vascular accessories.
- After Body Fluid Exposure Risk: Immediately after removing gloves following IV removal, cleaning blood or urine spills, or managing drainage containers.
- After Touching a Patient: Following positioning on the scanner couch, applying surface coils, or assisting the patient off the table.
- After Touching Patient Surroundings: After adjusting scanner control keypads, handling contaminated bore pads, touching gurney handrails, or operating contrast power injector touchscreens.
Alcohol-Based Hand Rubs (ABHR)
For routine clinical encounters, the CDC strongly recommends alcohol-based hand rubs (ABHR) over soap and water due to superior microbicidal efficacy, faster application time, and reduced skin irritation.
- Active Formulation: Formulations must contain between 60% and 95% ethanol or isopropanol.
- Mechanism of Action: Alcohols rapidly denature microbial proteins and disrupt cytoplasmic lipid membranes, effectively inactivating vegetative bacteria, enveloped viruses (e.g., Influenza, HIV, Coronaviruses), and fungi.
- Technique: Dispense the manufacturer-recommended volume (typically 3 to 5 mL, or a palmful) into a cupped hand. Vigorously rub all surfaces of both hands together—including palmar surfaces, dorsum of hands, interdigital web spaces, outer thumbs, fingernails, and wrists—until completely dry, commonly about 20 seconds. Never wave hands or wipe them with paper towels, because prematurely removing the product reduces effective contact.
Handwashing and C. difficile
Alcohol hand rub does not reliably kill C. difficile spores. Gloves, careful removal, environmental sporicidal cleaning and hand hygiene are all needed. CDC still favors alcohol-based hand sanitizer in most clinical situations when hands are not visibly soiled; it encourages soap-and-water handwashing after care during C. difficile outbreaks. Follow the infection-prevention team's outbreak and isolation policy, and always wash visibly soiled hands with soap and water. Do not describe every use of sanitizer after C. difficile care as a severe breach.
For handwashing, wet the hands, apply soap, rub all surfaces, rinse, and dry with a disposable towel. Use the towel to turn off a manual faucet. Plain soap can physically remove spores; antimicrobial soap is not universally required. Washing does not replace gloves for contact precautions. For alcohol hand rub, apply the labeled volume and rub all surfaces until dry, commonly about 20 seconds. Do not wipe the product away before it dries.
During a C. difficile outbreak, which hand-hygiene statement reflects CDC guidance?
Gloves eliminate hand hygiene
Soap-and-water washing after care is encouraged in addition to other infection measures
Alcohol rub reliably kills spores
Routine alcohol rub must be abandoned in every clinical situation
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