Experiment 2: Concepts of Quality Control and Safety in Serologic Testing Flashcards
Refers to the overall process of guaranteeing quality patient care and is regulated throughout the total testing system
QUALITY ASSESSMENT or QUALITY ASSURANCE (QA)
are the variables that occur before the actual testing of the specimen
Pre-analytical factors
Pre-analytical factors
• Test request
• Patient preparation
• Specimen collection, handling, and storage
are the processes that directly affect the testing of specimens.
Analytical factors
Analytical factors
• Reagents • Instrumentation and equipment: instrument calibration and maintenance • Testing procedure • Preventive maintenance • Access to procedure manuals • Competency of personnel performing the tests
o Refers to the materials, procedures, and techniques that monitor the accuracy, precision, and reliability of a laboratory test
Quality Control (QC)
are performed to ensure that acceptable standards are met during the process of patient testing
o QC procedures
• Used to verify the accuracy and precision of a test and are exposed to the same conditions as the patient samples.
is the ability to maintain both precision and accuracy
External quality controls
Reliability
(ability to obtain the expected result)
accuracy
(ability to obtain the same result on the same specimen)
precision
consists of internal monitoring systems built into the test system
Internal quality control
controls monitor the correct addition of a patient specimen or reagent, the instruments/reagents interaction, and test completion
• Internal or procedural
monitor a test system’s electronic or electric components
• Electronic controls
• The testing of unknown samples received from an outside agency
Proficiency testing
• It provides unbiased validation of the quality of patient test results
Proficiency testing
are processes that affect the reporting of results and correct interpretation of data.
Post-analytical factors
How close measurement is to true value
o Accuracy
How close results are when same sample is tested multiple times
o Precision
Range of values over which laboratory can verify accuracy of test system
o Reportable range
Formerly called normal value
o Reference interval
Lowest concentration of substance that can be detected by test method
o Analytical sensitivity
Ability of method to measure only analyte it is supposed to measure and not other related substances
o Analytical specificity
• Process of testing and adjusting analyzer’s readout to establish correlation between measured and actual concentrations
o Calibration
• Reference material with known concentration of analyte
o Calibrator
• Testing materials of known concentrations (calibrators, controls, proficiency testing samples, patient specimens with known values) to ensure accuracy of results throughout reportable range
o Calibration verification
• Test three (3) levels: high, midpoint, and low
o Calibration verification
• Required every 6 months, when lot number of reagents changes, following preventive maintenance or repair, and when controls are out of range
o Calibration verification
Positive results in a patient who has the disease
True Positive (TP)
Positive results in a patient who does not have the disease
False Positive (FP)
Negative results in a patient who does not have the disease
True Negative (TN)
Negative results in a patient who has the disease
False Negative (FN)
% of population with the disease that test positive
Diagnostic sensitivity
% of population without the disease that test negative
Diagnostic specificity
% of time that a pos itive result is corr ect
Positive predictive value (PPV)
% of time that a negative result is correct
Negative predictive value (NPV)
Study to verify accuracy of new method
o Correlation study
Schedule of maintenance to keep equipment in peak operating condition
o Preventive maintenance
Procedures specified by manufacturer to evaluate critical operating characteristics of test system
o Function checks
Comparison of patient data with previous results
o Delta checks
Other Components of QA Program
o Correlation study
o Preventive maintenance
o Function checks
o Delta checks
Study to verify accuracy of new method
o Correlation study
Schedule of maintenance to keep equipment in peak operating condition
o Preventive maintenance
Procedures specified by manufacturer to evaluate critical operating characteristics of test system
o Function checks
Comparison of patient data with previous results
o Delta checks
Types of Safety Hazard
Biological
Sharp
Chemical
Radioactive
Electrical
Fire/explosive
Physical
Infectious agents
Biological
Bacterial, fungal, viral or parasitic infections
Biological
Needles, lancets, and broken glass
Sharp
Cuts, punctures, or blood-borne pathogen exposure
Sharp
Preservatives and reagents
Chemical
Exposure to toxic carcinogenic or caustic agents
Chemical
Equipment and radioisotopes
Radioactive
Radiation exposure
Radioactive
Ungrounded or wet equipment and frayed cords
Electrical
Burns or shock
Electrical
Bunsen burners and organic chemicals
Fire/explosive
Burns or dismemberment
Fire/explosive
Wet floors, heavy boxes and patients
Physical
Falls, sprains and strains
Physical
o Denotes infectious materials or agents that present a potential health risk
BIOHAZARD/Biological Health Hazard
o Chain of infection and safety practices related to the
biohazard symbol
o Concern over exposure to blood-borne pathogens resulted in the drafting of guidelines and regulations by the (?) and the (?) to prevent exposure
Centers for Disease Control and Prevention (CDC)
Occupational Safety and Health Administration (OSHA)
The (?) guidelines describe four levels of biosafety depending upon the biological agents isolated or studied.
National Institutes of Health
The (?) are based on the virulence of the agents and the availability of effective treatments and vaccines
four levels of biosafety
laboratories handle agents that have no known potential for infecting healthy people.
- Biosafety Level 1 laboratories
are those laboratories that work with microorganisms associated with human diseases that are rarely serious and for which preventive or therapeutic interventions are often available.
- Biosafety Level 2 laboratories
is recommended for materials that may contain viruses not normally encountered in a clinical laboratory and for the cultivation of mycobacteria. Working with mycobacteria requires the use of N95 HEPA filter respirators.
- Biosafety Level 3
is required for work with dangerous and exotic agents that pose a high risk of aerosol-transmitted laboratory infections and life-threatening diseases for which effective treatments are limited.
- Biosafety Level 4
Exposure risks
• Accidental punctures with needles
• Spraying (aerosols) or spilling infectious materials onto desktop or floor
• Cuts or scratches from contaminated objects
• Centrifuge accidents: aerosols, broken tubes, etc.
all patients are considered to be possible carriers of blood-borne pathogens
o Universal Precautions (UP)
These guidelines are not limited to blood-borne pathogens; they consider all body fluids and moist body substances to be potentially infectious
Body Substance Isolation (BSI)
• Guideline describing personnel protective practices
Standard Precaution
o The guideline recommends wearing gloves when collecting or handling blood and body fluids contaminated with blood and wearing face shields when there is danger of blood splashing on mucous membranes and when disposing of all needles and sharp objects in puncture-resistant containers
Universal Precautions (UP)
o The CDC excluded urine and body fluids not visibly contaminated by blood, although many specimens can contain a considerable amount of blood before it becomes visible
Universal Precautions (UP)
personnel should wear gloves at all times when encountering moist body substances.
Body Substance Isolation (BSI)
o A major disadvantage is that they do not recommend handwashing following removal of gloves unless visual contamination is present
Body Substance Isolation (BSI)
o Present a serious biological hazard, particularly for the transmission of blood-borne pathogens
SHARP HAZARDS
Specimens that are POTENTIALLY infectious
o Blood
o Pus and purulent fluids
o Semen
o Vaginal secretions
o Cerebrospinal fluid
o Pleural fluid
o Peritoneal fluid
o Pericardial fluid
o Amniotic fluid
o Breast milk
Specimens that are usually NOT infectious (unless visibly bloody)
o Feces
o Nasal secretions
o Sputum
o Sweat
o Tears
o Urine
o Vomitus
is a law monitored and enforced by OSHA.
Occupational Exposure to Blood-Borne Pathogens Standard
Specific requirements of this OSHA standard include the following:
1. Requiring all employees to practice (?)
2. Providing laboratory coats, gowns, face and respiratory protection, and (?) gloves to employees and for nondisposable protective clothing
3. Providing (?) and prohibiting recapping of needles
4. Prohibiting eating, drinking, smoking, and (?), lip balm, and contact lens in the work area
5. Labeling all (?) material and containers
6. Providing free immunization for (?)
7. Establishing a (?) for work surfaces; an appropriate disinfectant for blood-borne pathogens is
8. Providing (?) for employees who have been accidentally exposed to blood-borne pathogens
9. Documenting (?) in safety standards for employees
UP/Standard Precautions
laundry facilities
sharps disposal containers
applying cosmetics
biohazardous
HBV
daily disinfection protocol
medical follow-up
regular training
§ Any accidental exposure to a possible blood-borne pathogen must be
immediately reported
§ Evaluation of the incident must begin right away to ensure appropriate
post-exposure prophylaxis (PEP)
