Laboratory Safety and Chain of Infection (P) Flashcards
What are biological hazards?
A biological substance that poses a threat to the health of humans by exposure to harmful microorganisms or infectious agents
What are the different sources of biological hazards in healthcare facilities?
1) Patients
2) Medical devices and equipment
3) Specimen
4) Water sources and irrigations
5) Vents and air conditioning
6) Fomites
What is chain of infection?
A process by which infection is spread in a community at a given period
What are the components that are required for continuing the chain of infection?
- Source
- Method of transmission
- Susceptible host
Explain the process of chain of infection
Transmission occurs when the agent leaves its reservoir or host through a portal of exit, is conveyed by some mode of transmission, and enters through an appropriate portal of entry to infect a susceptible host
What are the components of chain of infection?
1) Infectious agent
2) Reservoir
3) Portal of exit
4) Mode of transmission
5) Portal of entry
6) Susceptible host
What are infectious agents?
Potentially harmful microbes
What are the examples of infectious agents?
- Bacteria (pathogens)
- Viruses
- Fungi
- Protozoa
What is reservoir?
Habitat in which the infectious agent normally lives, grows, and multiplies
Is reservoir the source of infectious agent being transmitted?
It may and it may not be the source of the infectious agent that is being transmitted
Provide an example of reservoir
Clostridium botulinum (botulism)
What are the different types of reservoir?
1) Human reservoir
2) Animal reservoir
3) Environmental reservoir
What is human reservoir?
May or may not show the effects of illness
What are the different types of human reservoir?
1) Carrier
2) Asymptomatic or passive
3) Incubatory carriers
4) Convalescent carriers
5) Chronic carriers
What is a carrier?
A person with inapparent infection who is capable of transmitting pathogen to others
What are asymptomatic or passive carriers?
Also called as healthy carriers
Those who never experienced symptoms despite being infected
What are incubatory carriers?
Those who can transmit the agent during the incubation period before clinical illness begins
What are convalescent carriers?
Those who have recovered from their illness but remain capable of transmitting to others
What are chronic carriers?
Those who continue to harbor a pathogen such as Hepatitis B virus or Salmonella Typhi for months or even years after their initial infection
Is animal to animal transmission of diseases possible?
Yes
In the case of animal reservoirs, human serves as what?
Incidental hosts / accidental hosts
What is zoonosis?
An infectious disease that is transmissible under natural conditions from vertebrate animals to humans
What are the examples of zoonotic diseases?
1) Brucellosis
2) Anthrax
3) Plague
4) Trichinellosis / trichinosis
5) Tularemia
6) Rabies
Who or what are the reservoir of brucellosis?
Cows and pigs
Who or what are the reservoir of anthrax?
Sheep
Who or what are the reservoir of plague?
Rodents
Who or what are the reservoir of trichinellosis or trichinosis?
Swine
Who or what are the reservoir of tularemia?
Rabbits
Who or what are the reservoir of rabies?
Bats, racoons, dogs, and other mammals
What are the examples of environmental reservoirs?
1) Plants
2) Soil
3) Water
What are the fungal agent that can live and multiply in the soil?
Fungal agents that cause histoplasmosis
What infectious agents are present in water?
Legionella pneumophila (causative agent of Legionnaires disease)
What is portal of exit?
1) The path by which a pathogen leaves its host
2) Usually corresponds to the site where the pathogen is localized
What are the examples of portal of exit?
1) Respiratory tract
2) Urine
3) Feces
4) Skin lesions
5) Crossing of placenta (transmission via the placenta)
6) Cuts or needles
7) Blood-sucking arthropods
What are the infectious agents that can be transmitted via the respiratory tract?
1) Influenza viruses
2) Mycobacterium tuberculosis
What are the infectious agents that can be transmitted via urine or feces?
Schistosomes
What are the infectious agents that can be transmitted via feces?
Vibrio cholerae
What are the infectious agents that can be transmitted via skin lesions?
Sarcoptes scabiei
What are the infectious agents that can be transmitted via the placenta (crossing of placenta)?
1) Rubella
2) Syphilis
3) Toxoplasmosis
What are the infectious agents that can be transmitted via cuts or needles in the skin?
Hepatits B
What are the infectious agents that can be transmitted via blood-sucking arthropods?
Malaria
What is mode of transmission?
The method on how an infectious agent is transmitted
What are the different classifications of modes of transmission?
1) Direct (direct contact)
2) Indirect (indirect contact)
What is direct contact as mode of transmission?
1) Occurs through skin-to-skin contact such as kissing and sexual intercourse
2) Contact with soil or vegetation harboring infectious organisms
What are the infections or diseases that can be transmitted via direct contact (person to person)?
1) Infectious mononucleosis (kissing disease)
2) Gonorrhea
What is the infectious agent or pathogen that can be transmitted via direct contact with contaminated soil?
Hookworm
What are the different classifications of direct contact (mode of transmission)?
1) Direct contact
2) Droplet spread
What is droplet spread (mode of transmission)?
Refers to spray with relatively large, short-range aerosols produced by sneezing, coughing, or even talking
Why is droplet spread classified as direct contact?
Because transmission is by direct spray over a few feet, before the droplets fall to the ground
What are the examples of infectious agents that can be transmitted via droplets?
1) Pertussis
2) Meningococcal infection
3) SARS and SARS-COV2 infections
What is indirect transmission (mode of transmission)?
The transfer of an infectious agent from a reservoir to a host by suspended air particles, inanimate objects (vehicles), or animate intermediaries (vectors)
What is airborne transmission?
Occurs when infectious agents are carried by dust or droplet nuclei (5 microns) suspended in air and may be blown over great distances
What are the infectious agents that can be transmitted via airborne transmission?
1) Measles
2) Tuberculosis
3) Influenza
4) Colds
5) Chickenpox
What are vehicles (mode of transmission)?
May indirectly transmit an infectious agent
What are the example of vehicles (mode of transmission)?
1) Food
2) Water
3) Biologic products (blood)
4) Fomites (inanimate objects)
What are vectors (mode of transmission)?
Organisms that may carry an infectious agent through purely mechanical means or may support growth or changes in the agent
What are the examples of vectors (mode of transmission)?
1) Mosquitoes
2) Flies
3) Ticks
What are the two types of transmission via vectors?
1) Mechanical transmission
2) Biologic transmission
What is mechanical transmission (mode of transmission)?
Example of this are flies which carries Shigella on their appendages and fleas carrying Yersinia pestis in their gut
What is biologic transmission (mode of transmission)?
The principle of this is that the causative agent of malaria or guinea worm disease undergoes maturation in an intermediate host before it can be transmitted to humans
What is portal of entry?
1) Refers to the manner in which a pathogen enters a susceptible host
2) Must provide access to tissues in which the pathogen can multiply or a toxin can act
Often, infectious agents use the same portal of entry to enter a new host that they used to exit the source host. What are the examples of these infectious agents and what are their portal of entries?
1) Influenza, tuberculosis, COVID 19 -> respiratory tract
2) Gastroenteritis, intestinal infections -> fecal-oral route
3) Hookworm -> skin
4) Syphilis -> mucous membranes
5) Hepatitis B and human immunodeficiency virus (HIV) -> blood
What is a susceptible host?
1) The final link in chain of infection
2) The host that is being infected by infectious agents or pathogens
What are the factors that contributes to the susceptibility of a host which affects the ability of a host to resist such infection or to limit the pathogenicity of an infectious agent?
1) Genetic or constitutional factors
2) Specific immunity
3) Nonspecific factors
How can the genetic makeup of an individual affect with regards to his / her susceptibility?
An individual’s genetic makeup may either increase or decrease susceptibility
Who are often considered as more susceptible hosts?
1) Immunocompromised patients
2) Newborn and infants
3) Elderly
What are the different types of safety hazard in the lab?
1) Biologic
2) Sharps
3) Chemical
4) Radioactive
5) Electrical
6) Fire / Explosive
7) Physical
What are the sources for biologic hazards?
Infectious agents
What are the sources for sharps hazards?
1) Needles
2) Lancets
3) Broken glass
What are the sources for chemical hazards?
1) Preservatives
2) Reagents
What are the sources for radioactive hazards?
1) Equipment
2) Radioisotopes
What are the sources for electrical hazards?
1) Ungrounded or wet equipment
2) Frayed cords
What are the sources for fire or explosive hazards?
1) Open flames
2) Organic chemicals
What are the sources for physical hazards?
1) Wet floors
2) Heavy boxes
3) Patients
What are the possible injuries that may be obtained via biologic hazards?
1) Bacterial infections
2) Fungal infections
3) Viral infections
4) Parasitic infections
What are the possible injuries that may be obtained via sharps hazards?
1) Cuts
2) Punctures
3) Blood-borne pathogen exposure
What are the possible injuries that may be obtained via chemical hazards?
Exposure to toxic, carcinogenic, or caustic / corrosive agents
What are the possible injuries that may be obtained via radioactive hazards?
Radiation exposure
What are the possible injuries that may be obtained via electrical hazards?
Burns or shock
What are the possible injuries that may be obtained via fire or explosive hazards?
Burns or dismemberment
What are the possible injuries that may be obtained via physical hazards?
1) Falls
2) Sprains
3) Strains
What are the standard precautions that can be done inside the lab?
1) Handwashing
2) Wearing of gloves
3) PPE -> mask, eye protection (goggles), and face shield
4) Gown
5) Patient care equipment
6) Environmental control
7) Linen
8) Occupational Health and Blood Borne Pathogens
- > sharps container
- > proper disposal of sharps
9) Patient placement
- > isolation
What are the standards for Occupational Exposure to Blood Borne Pathogens Standard?
1) Requiring all employees to practice UP / standard precautions
2) Providing lab coats, gowns, face, and respiratory protection, and gloves to employees and laundry facilities for non-disposable protective clothing
3) Providing sharps disposal containers and prohibiting recapping of needles
4) Prohibiting eating, drinking, smoking, and applying cosmetics, lip balm, and contact lens in the work area
5) Labelling all biohazardous material and containers
6) Providing free immunization for HBV
7) Establishing a daily disinfection protocol for work surfaces; an appropriate disinfectant for blood-borne pathogens is sodium hypochlorite (household bleach diluted 1:10)
8) Providing medical follow-up for employees who have been accidentally exposed to blood-borne pathogens
9) Documenting regular training in safety standards for employees
What are the proper ways or applications when it comes to chemical handling?
1) Acid should always be added to water to avoid the possibility of sudden splashing caused by the rapid generation of heat in some chemical reactions.
2) Wearing goggles and preparing reagents under a fume hood are recommended safety precautions
3) Chemicals should be used from containers that are of an easily manageable size.
4) Pipetting by mouth is unacceptable in the laboratory
What is the meaning of MSDS?
Material Safety Data Sheet
What are the components of MSDS?
1) Physical and chemical characteristics
2) Fire and explosion potential
3) Reactivity potential
4) Health hazards and emergency first aid procedures
5) Methods for safe handling and disposal
What is radioactivity (radioactive hazards)?
Encountered in the clinical lab when procedures using radioisotopes are performed
Is radioactivity present in labs?
Yes, but its amount is very small and presents little danger
Are the effects of radiation cumulative?
Yes, and these effects are related to the amount of exposure
The amount of radiation exposure is related to what?
1) Combination of time
2) Distance
3) Shielding
What device is required for personnel working in a radioactive environment?
Measuring devices
What is the purpose of measuring devices in a radioactive environment?
To determine the radiation that the personnel are accumulating
Provide an example of application that may pose electrical hazard
The danger of water or fluid coming in contact with equipment (greater chances in labs)
Is it okay to operate equipment with wet hands?
No
Who is responsible for monitoring electrical equipment?
Designated hospital personnel
What should a lab personnel do to prevent occurrence of electrical hazards?
Observe for any dangerous conditions (such as frayed cords and overloaded circuits, and report them to appropriate persons)
What should be done if an equipment become wet?
It should be unplugged and allowed to dry completely before reusing
What should be done to an equipment before cleaning?
It should be unplugged
What should be done to all electrical equipment?
Must be grounded with three pronged
What should be done when an accident involves electrical shock occurs?
1) The electrical source must be removed immediately
2) This must be done without touching the person or the equipment involved
How to operate a fire extinguisher?
PASS
1) Pull the pin
2) Aim at the base of the fire
3) Squeeze handles
4) Sweep nozzle side to side
What are the general safety practices that will reduce the risk of inadvertent contamination with blood or body fluids?
1) Staff must wear laboratory coats and be additionally protected from contamination by infectious agents.
2) Food and drinks should not be consumed in work areas or stored in the same area as specimens. Containers, refrigerators, or freezers used for specimens should be marked as containing a biohazard.
3) Specimens needing centrifugation are capped and placed into a centrifuge with a sealed dome.
4) A gauze square is used when opening rubber-stoppered test tubes to minimize aerosol production (introduction of substances into the air).
5) Autodilutors or safety bulbs are used for pipetting.
- > Pipetting of any clinical material by mouth is strictly forbidden
What are the different protective techniques for infection control (in tems of selection and use of gloves)?
Selection and Use of Gloves
- Gloves for medical use are sterile surgical or nonsterile examination gloves made of vinyl or latex.
- Latex gloves provides more tactile sensitivity ;however, either type is usually satisfactory for phlebotomy and as a protective barrier during technical procedures.
- Latex-free gloves should be available for personnel with sensitivity to usual glove material.
- Rubber household gloves may be used for cleaning procedures
What are the guidelines related to the selection and general use of gloves?
1) Use sterile gloves for procedures involving contact with normally sterile areas of the body or during procedures in which sterility has been established and must be maintained.
2) Use nonsterile examination gloves for procedures that do not require the use of sterile gloves. Gloves must be worn when receiving phlebotomy training.
- > The National Institute of Occupational Safety and Health Administration (OSHA) mandates the use of gloves for phlebotomy.
3) Gloves should be changed between each patient contact.
4) Wear gloves when processing blood specimens, reagents, or blood products, including reagent red blood cells.
5) Gloves should be changed frequently and immediately if they become visibly contaminated with blood or certain body fluids or if physical damage occurs.
6) Do not wash or disinfect latex or vinyl gloves for reuse.
- > Rubber gloves may be decontaminated and reused, but disinfectants may cause deterioration. Rubber gloves should be discarded if they have punctures, tears, or evidence of deterioration or if they peel, crack, or become discolored.
7) Using items potentially contaminated with human blood or certain body fluids (e.g., specimen containers, lab instruments, countertops
8) Gloves should be properly removed or covered with an uncontaminated glove or paper towel before answering the telephone, handling laboratory equipment, or touching doorknobs
What is the proper handwashing technique or process?
1) Palm to palm
2) Between fingers
3) Back of hands
4) Base of thumbs
5) Back of fingers
6) Fingernails
7) Wrists
8) Rinse and wipe dry
What is the proper way of donning PPE?
1) Sanitize or wash hands
2) Wear the protective gown
3) Wear the mask. Ensuring that no air leakage at the upper part and lower chin.
4) Wear the eye goggle or face shield.
5) Wear the shoe cover if needed.
6) Wear the gloves.
What is the proper way of doffing PPE?
1) Remove gloves. Using one hand, grasp the palm of the other hand and peel off the first glove.
2) Perform hand hygiene.
3) Remove gown.
4) Perform hand hygiene.
5) Exit the patient’s room and close the door.
6) Remove goggles/face shield.
7) Perform hand hygiene.
8) Remove mask/respirator
How to properly decontaminate working areas?
- All work surfaces should be cleaned and sanitized at the beginning and end of the shift with a 1:10 dilution of household bleach
- Instruments such as scissors or centrifuge carriages should be sanitized daily with a diluted solution of bleach
What is the purpose of diluted household bleach?
Inactivates HBV in 10 minutes and HIV in 2 minutes
Where should disposable materials contaminated with blood be disposed?
In containers marked as “Biohazard” and should be properly discarded
Where should infectious wastes be disposed?
These must be disposed into proper biohazard containers with the following features:
1) Conspicuously marked “Biohazard” with the universal biohazard symbol
2) Universal color—orange, orange and black, or red
3) Rigid, leakproof, and puncture resistant.
4) Used for blood and other potentially infectious body fluids, as well as disposable materials contaminated with blood or fluid
