Quality Flashcards
What is Health Canada responsible for?
Health Canada is responsible for helping Canadians maintain and improve their health. It ensures that high-quality health services are accessible, and works to reduce health risks.
What does the ‘Regulated Health Professions Act’ do?
regulates health professionals to provide health services in a safe, professional, and ethical manner in the public interest.
What does the ‘College of American Pathologists’ (CAP) Laboratory Accreditation Program provide?
provides an on-site inspection to assess compliance with program requirements using discipline specific CAP Accreditation Checklists
What is the ‘Manitoba Quality Assurance Program’?
Manitoba Quality Assurance Program (MANQAP) establishes standards for diagnostic facilities, investigates and inspects diagnostic facilities for accreditation, and monitors compliance with established Manitoba Laboratory Standards and the Manitoba Patient Service Center Standards.
What is ISO 15189?
ISO 15189 Medical laboratories – Requirement for quality and competency is an international standard that specifies the quality management system requirements particular to medical laboratories developed by the International Organization for Standardization.
What is the ‘Clinical Laboratory Standards Institute’?
Clinical Laboratory Standards Institute promotes the development and use of voluntary laboratory consensus standards and guidelines within the health care community.
What is a Quality Management System?
Overseeing all activities and tasks to achieve excellence
Includes quality assurance and quality control
What is Quality Assurance?
Activities and processes implemented to ensure quality through every stage of the process (prevention of errors)
Auditing
What is Quality Control?
Operational techniques to fulfill quality requirements (detection of errors)
Includes statistical monitoring and proficiency testing
Quality control ensures that laboratory tests produce accurate and precise results using a statistical control system for recognizing and minimizing analytical errors
Name at least four quality system essentials?
Organization Process Management Customer Focus (e.g. patient) Facilities and Safety Documents and Records (e.g. standard operating procedures, maintenance records) Information Management Personnel (properly trained) Purchasing and Inventory Equipment Nonconforming Event Management Assessments (e.g. analyze patient data vs control - validation) Continual Improvement
What is risk management?
Risk management is the systematic application of management policies, procedures and practices to the tasks of analyzing, evaluating, controlling, and monitoring risk.
What is one way to reduce risk in the lab mentioned in this class?
Development of a comprehensive quality plan for the:
Prevention of laboratory testing errors
Ensures that correct results are reported
What are potential areas for risk pre-analytical, i.e. before testing?
Patient preparation Fasting or time of day Collection of sample and handling Patient ID, posture, warming site, order of draw, proper tubes for proper test, tube inversions, hemolysis, Transport On ice, type of container, time to lab Accessioning Entered into LIS correctly, labelled correctly Processing of sample prior to testing Centrifuging, aliquoting Storage
What are potential areas for risk during the analytical phase?
Testing
Reliable methods
Water quality, temperature monitored, pipettes calibrated, instrument maintained and checked
Standard Operating Procedures (SOPs) clear
Staff thoroughly trained
What are the potential areas for risk during the post-analytical phase?
Following testing Interpretation of results Repeat testing if necessary Delta checks Reporting results Correcting errors Turn around time Sample arrives in lab until results are sent out
Describe the risk management process?
See slide 13 of Quality Presentation
- Hazard Identification, begins with process map of lab process steps,
- Risk estimation of each step, likelihood of failure, severity of patient harm from failure
- Risk controls (labs), and lastly,
- Risk monitoring and failure investigation
What is a NCEs (non-conformance event)?
Deviation from established policies and procedures. Within a QMS NCEs are documented, investigated, and used to improve the quality of laboratory services
Learn from them and change policies or procedures to prevent future NCEs
What are some examples for non-conformance events in a lab setting?
Unlabeled and/or mislabeled samples
Specimen processing errors
Incorrect results reported
Reports faxed to incorrect office
What is done at a quality assessment? Why is it important.
Update the Risk Assessment/Management and modify the Quality Control Plan (QCP) based on information obtained from the Quality Assessment
Important for accreditation
What is used to decrease waste and errors in the lab while increasing value?
A combination of Lean and Six Sigma principles.
Lean: Streamlining or modifying to reduce cost
Errors cost money and time
Does this process or step need to exist?
Six Sigma or 6SDs
Test with a determined 6SD performance will be very precise and produce only 3.4 occurances for every million opportunities performed or a 99.9997% yield
What are some examples of wastes in the lab (name at least two)?
Waiting – time between processes and tests
Excess motion – unnecessary movements
Overproduction – excess work in progress (specimens piling up in processing area)
Defect correction – time and resources to correct issues
Excess processing – unnecessary steps in process that doesn’t add value
Excess movement of materials – moving materials from one place to another
Inventory – over-ordering or keeping excess items on hand that will not be used
What are the 5S’ of the lean process?
Sort – remove unnecessary items
Straighten – arrange items so they are easily accessible
Shine – maintaining a clean space
Standardize – organization with clear/detailed procedures and proper training
Sustain – time commitment and effort by employees and employer
Name at least two things included in a quality control plan in a lab?
Defined Standard Operating Procedures (SOPs) and policies
Identify and control variables in the system
Pipette and instrument calibrations, water quality, etc.
Proficiency testing
Frequency and evaluation method for quality control data
Detection, troubleshooting, and corrective actions
Schedule for routine maintenance
Record keeping and record retention
Maintenance Logs, Calibrations, QC Charts, refrigerator/freezer temps, etc.
What are parts of an Internal Quality Control Program for a lab?
Determine frequency of QC testing
Type and number of QC samples that will be tested
Statistical QC limits
Corrective actions if QC is not acceptable
What are parts of an External Quality Control Program for a lab?
Proficiency Testing
Compare results to other labs with same testing methodology
PT treated like unknown patient sample
Demonstrates technical competence
Evaluates internal QC program and helps identify potential areas of improvement
Confidence in the accuracy of the laboratory’s testing results or detection of error in the lab method
Verification of the effectiveness of training
What are quality control materials?
- Stabilized sample with a known range of results that is tested like a patient’s sample.
- Validates patients results and used to help detect errors with the equipment, reagent, technique, etc.
Controls cannot be used as calibrators or standards.
What qualities should a control material have?
- Available in aliquots or vials in STABLE form
- Able to be used for analysis over an EXTENDED period of time
- Have the same MATRIX (same chemical and physical characteristics) as the test sample, e.g. Urine versus plasma versus CSF
- Available in MULTIPLE LEVELS that cover the range of results required to be validated for an analyte. Example: low, normal, and high OR normal and abnormal
What is accuracy?
- Closeness to true value
2. Detects: Systematic errors & Bias
What is precision?
- Agreement of test results upon replicate testing (consistent results)
- Detects: Random errors and SD and %CV
What is reliability?
Reliability is the degree of accuracy and precision over an extended period of time.
What is mean versus the median versus mode?
Mean – average of data points
Mode – value which occurs most frequently
Median - middle value if the observed values are arranged in increasing order
What is standard deviation?
SD – amount of variance from the mean value in a set of values
Don’t want it to be too narrow (false rejection) or too wide (false acceptance)
Data points should fall within the following distribution or Gaussian (Bell-shaped) Curve
+ 1SD = 68.2%
+ 2SD = 95.5%
+ 3SD = 99.7%
What is CV?
CV - standard deviation expressed as a percentage of the mean
Often used to measure the variability or precision of a method or instrument
How do you establish range?
Establish range (mean, SD, and CV) by running QC 20 times or 20 days Accounts for day-to-day variations (different MLTs, reagent changes, instrument maintenance, etc.)
What are the Westguard Multi-Rule Approach if three control sets are being used?
Look at slide 31 for definitions of
12s, 13s, 2 of 3 22s, R4s, 31s, 6x.
What is a trend? Name examples of causes.
Trend:
- Exists when six or more consecutive control values increase or decrease by moving in one direction above or below the mean
- Slow movement
Example: reagent or control deterioration
What is a shift?
Shift:
- Occurs when more than six consecutive control values maintain a constant level above or below the mean
- Sudden change
Example: instrument malfunction, loss of calibration, or improper reagents
What are systematic errors? Name some potential sources.
- Reproducible inaccuracies consistently in the same direction
- May be due to: Change in reagent lot number, calibration issue, instrument deterioration (optical, voltage, wear and tear), aging reagents or calibrators, etc.
- -> Check lot numbers, check expiration, calibrate, etc.
What are random errors? Name some potential examples.
- Statistical fluctuations in either direction due to precision limitations of the measurement device
- Examples: Bubbles, temperature variations, instrument instability, human error, reagent dispensing error, sample evaporation, etc.
- -> Re-test
What is calibration?
Calibration:
1. Reference material of known concentrations (calibrators) are used to set the measurement of a method/device to a known reference to ensure accuracy and precision.
2. Accuracy must be ensured throughout the reportable range.
Result determines: Range instrument or method can accurately determine measurements
When do you need to re-caliberate?
When to re-calibrate?
- With a new lot number of reagents
- Quality control shows evidence of a systematic error: Investigate > resolve > calibrate > run QC > assess QC
- Major repairs on instruments
- Certain analytical tests time out (ie. calibration expires)
- Some methods may have calibrators on every run!
Are all quality control done in lab quantitative?
- No, not all quality control done in the lab is quantitative, so we cannot always rely on Westgard rules (which uses statistics).
- Non-Westgard rules are implemented for qualitative tests:
a. Absence or presence of analyte
b. Positive or negative result
What is an example of a qualitative quality control test?
Gram Stain:
Positive control: Staphylococcus aureus = gram positive cocci in clusters
Negative control: Escherichia coli = gram negative bacilli
You can determine if slide is over- or under de-colourized.
Could impact your interpretation and which flow chart you follow to ID
Must interpret and pass QC prior to reading and interpreting unknown
What are reference ranges? What are they used for? Other terms for the same thing?
- Concentration of analyte found in a group of clinically “normal” or apparently healthy persons
- Results for diagnosis are compared to the reference range
Aka Normal Range, Normal Values, Reference Values, Reference Limits or Reference Intervals
What are reference ranges based on?
- Ranges vary depending on population and location
- “Normal” in one area may be difference than another
- Based on: age, sex, race, pregnancy, medication, smoking, drinking, fasting or not, time of day, season, posture, physical activity, specimen collection & processing, method of analysis
How are reference ranges used?
- Values outside of reference range, can be checked and/or phoned to ward or physician.
- If results are incompatible with life –> contamination or sample integrity may be questioned.
How are reference ranges determined?
Determination of Reference Range:
1. Measurement of analyte from at least 120 “normal” individuals. Determine eligibility criteria. Exclude those with risk factors ie. hypertension or those who take medications
2. Statistical analysis used. Normal Gaussian distribution or bell curve should result. Reference range will be +/- 2SD from the mean.
Note: Large centers may determine own range. Small labs may run a smaller number of samples to verify their values correlate.
What are delta checks? What is one example of a good analyte to do delta checks with?
- QC tool that compares current test results with previous test results on the same patient. Big changes could be used to detect:
a. Patient pathology
b. Issues with testing
c. Issues with sample
d. Wrong patient, accessioned incorrectly, sample integrity issue (clotting), etc. - Note: only a good tool on stable analytes that don’t have day-to-day variations. Example: MCV in Hematology
What is method validation?
Method validation is the process of determining if an analytical procedure is consistently reliable in producing quality laboratory results.
What can linear regression (y=mx+b) be used for?
- Linear regression can be used to:
Determine line of best fit (standard or calibration curve) to estimate unknown values. - Determining reportable range and linearity.
- Compare two different methods.
Reference method along x axis
New/test method along y axis
What statistical value is used to quantify the strength of a linear relationship between two methods of measurement?
Strength of the relationship is indicated by the correlation coefficient = r
r = -1 means inverse relationship
r = 0 means no relationship
r = +1 means positive correlation
What is correlation of determination?
- The correlation of determination (R2) indicates the proportion of variation from one variable to another.
- Ranges from 0 to 1. 0.95 would be a line that represents the data well.
- Aim for > 0.98 in clinical chemistry.
What information about quality can be gained from linear regression?
- Provides information about error between the methods or expected results
- Systematic error = changes in the y-intercept and slope
- Random error = greater distance of data points away from the regression line
Referred to as standard error of the estimate Sy/x. The higher the Sy/x the wider the scatter the higher the amount of random error.
What is specificity and how do you calculate it?
- Ability of a method to measure only the analyte of interest
- % of individuals without the condition being test for, who will have a negative test
More specific = fewer false positives
Calculation: [TN ÷ (TN + FP)] x 100
What is Sensitivity? How do you calculate it?
- Ability to measure small quantities of an analyte.
- % of individuals who do have the condition or disease. More sensitive = fewer false negatives.
Calculation:
[TP ÷ (TP + FN)] x 100
Positive Predictive Value
Probability of an individual having the disease if the result is positive
Calculation:
[TP ÷ (TP + FP)] x 100
Negative Predictive Value
Probability of an individual not having the disease if the result is negative
Calculation:
[TN ÷ (TN + FN)] x 100
