Quality assurance and Quality control

Quality assurance

• This refers to all the processes a laboratory undertakes to ensure the quality of the test

results.

• It is the RESULT of the processes focused on achieving quality.

• oversees all of the procedures in the laboratory to ensure that the results released are accurate and precise.

1. Quality Laboratory Processes or Planning (QLP)

2. Quality Assessment or Assurance (QA)

3. Quality Improvement (QI)

4. Quality Control (QC)

Four disciplines of quality management framework:

Quality laboratory Processes or Planning

• Personnel policies

• Standard operating procedures

• Specimen collection guidelines

Quality improvement

• It determines the cause of the problem (detects the error first).

• Provides input to further quality planning to eliminate the problem.

Quality control

• Provides the tools to detect problems early and prevent errors from exceeding established quality requirements.

• defined as the monitoring of work processes, detecting problems, and making corrections before the delivery of products or services.

TRUE

TRUE or FALSE: QC is applied to the analytical process and not the pre-analytical or post-analytical phases.

1. Internal Quality Control

2. External Quality Control

Two types of quality control:

Internal quality control

• control within the laboratory

External quality control

This process ensures long-term accuracy and consistency of laboratory results, even for trained professionals.

Lung Center of the Philippines (LCP)

In the Philippines, proficiency testing samples used for external quality assessment (EQA) come from the?

1. control

2. standard

Quality control monitoring consists of?

Standard

a solution that contains a known amount of an analyte, and it is used to calibrate an assay method.

Control

are patient-like substances run alongside patient samples to monitor the performance of an assay method once it has been calibrated

Daily

Quality control has to be performed?

28 days

When calibrating the analyzer, do it every?

Level 1 (low/normal) and Level 2 (normal/high) control materials

The medtech should perform quality control daily (once per day) using?

20 consecutive days

The minimum number of days for running quality control is at least?

Matrix interference

is a control that does not act like a biological sample.

• expired reagents

• operator technique

One common error in the laboratory is?

1. Level 1 (yellow vial): Low to normal range

2. Level 2 (red vial): Normal to high range

3. Level 3 (if available): Significantly elevated range

QC vials come in levels with defined target ranges:

tests the analyzer’s capability before running actual patient samples

Purpose of quality control

once daily

If using Level 1 and Level 2, run the QC how many times?

twice daily

If using Level 1 only, run the QC how many times?

• Mean

• Median

• Mode

These values help to determine the typical or central value of a data set, based on a minimum of 20 days of QC runs, with one run per day.

Mean

• is defined as the average of all the data points or values.

• Sum of all the values divided by the total number of values (n).

Median

Defined as the middle data point observed once the data are arranged in descending or ascending order

Mode

is the value that occurs with the greatest frequency

• Range

• Variance

• Standard deviation

• Coefficient of variation

These values describe how spread out the data points are.

Range

Defined as the difference between the highest and lowest value in a data set.

Variance

• is defined as the measure of the average squared distance of data points from the mean.

• This measures how far each number in the set is from the mean

Standard deviation

• is a measurement statistic that describes the average distance each data point in a normal distribution is from the mean.

• measures how far the QC values are from the mean (average)

Confidence limits

defined as the limits between which we expect a specified proportion of a population to lie

Coefficient of variation

• is the standard deviation expressed as a percentage of the mean

•  is useful for comparing the precision of different laboratory tests or different labs.

Scheduling of staff

Which of the following monitoring factors would NOT be included in a laboratory’s quality assessment program?

Standard deviation

Which of the following terms refers to the measure of scatter of experimental data around the mean of the Gaussian (Normal) Distribution Curve?

Accuracy

• Ability to obtain the established or “TRUE” value for a sample.

• Correctness of a result.

Precision

• Ability to obtain the same value for repeat measurements of a sample.

Levey-Jennings charts

• also referred to as a Gaussian distribution curve

• s a monitoring tool to monitor or diagnose problems in the analyzer.

• used to monitor QC data over time

Trend

Gradual change in the mean that proceeds in one direction.

Shift

An abrupt change in the mean that becomes continuous.

Multi-rule systems

• define specific limits for control values.

• Used for accepting or rejecting a control run.

1. Random error

2. Systematic error

Types of error:

Random error

• Non-recurring errors.

• An error that occurs without any real pattern.

• An error that may occur at any time and place within the production process.

• Pipetting

• Improper handling of specimens and reagents.

• Voltage and temperature fluctuations in the laboratory.

• Dirty optics

• Presence of bubbles

Causes of random error:

Systematic error

• Recurring errors.

• An error that occurs in a predictable pattern or direction.

• An error that is continuous and affects all results equally.

• Improper calibration

• Expired reagents

• The solution is contaminated.

• Incorrect sample and reagent volume.

Causes of systematic error:

1-2S

• One control value exceeds the mean by more than 2SD but less than 3SD in either the upward or downward direction. (example – outlier)

• Random error

1-3S

• One control value exceeds the mean by more than 3SD in either the upward or downward direction.

• Random error

2-2S

• Two consecutive control values exceed the mean by more than 2SD but less than 3SD.

• Systematic error

R-4S

• The difference between two consecutive controls is greater than 4SD.

• Random error

4-1S

• Four consecutive control values exceed the mean by more than 1SD.

• Systematic error

10x

• Ten consecutive control values exceed the mean in the same direction.

• Systematic error

• changes to the test system

• deterioration of reagents or calibrators.

Causes of trend:

Delta check

• Assess the patient’s most recent result for a particular test as compared to the patient’s previous value.

• method of verifying a patient's current test result by comparing it to their previous results. 

• Useful for identifying significant changes that may indicate a problem with the specimen, an error in the test, or a rapid change in the patient's condition.

Youden plot

• A graphical technique for analyzing interlaboratory data when each laboratory has made two runs on the same analyte or one on two different analytes.

• Plot identifies the variability within the laboratory and between laboratories.

Sensitivity

• The percentage of individuals with a specific disease that are correctly identified or predicted by the test as having the disease.

• Studying the percentage of individuals who have the disease.

• is computing for the positivity of the disease, meaning having the disease.

Specificity

• It is the percentage of individuals without the specific disease that are correctly identified or predicted by the test as not having the disease.

• is computing the percentage of individuals without the disease, meaning negativity.

• Detect the population that actually does not have the disease.

1. Pre-Analytical

2. Analytical

3. Post-Analytical

3 phases of quality assurance program

Identify what phase in QA:

• Correct ordering of tests.

• Preparation of the patient.

• Correct identification of the patient.

• Proper collection of the sample

• Timely transportation of the sample to the laboratory.

• Proper handling of the sample from the time of transportation to the time of analysis. 

• Proper handling of the sample within the laboratory

Analytical phase

identify what phase in QA:

• involves the assay itself.

• Proper labeling and use of reagent

• Periodic calibration of pipetting devices

• Periodic calibration of pipetting devices

• Periodic checking of the temperatures of refrigeration units.

• Periodic checking of the accuracy of all analytical balances and thermometers.

• Periodic checking of the accuracy of centrifuge speeds and timing devices.

• Periodic checking that procedure manuals are complete and up-to-date.

• Constant assurance that safety procedures are followed.

Post-analytical phase

Identify what phase in QA:

• refers to the results, and the physician will interpret those results.

• Verification of calculations on final reports.

• Review of test results for possible transcription errors. 

• Reports that are easy to read and interpret.

• Procedures for informing the physician of results that require immediate attention. 

• Timeliness of reporting values to the patient chart.

Amendments of 1988 (CLIA)

• Determines the limits of allowable error.

• Determine the limits of acceptable error.

Six sigma methodology

• y a manufacturing strategy.

• It was pioneered by the Motorola company, with one of its engineers, Bill Smith.

• improves the production efficiency of different industries by converting the problems into a mathematical equation.

• aims to improve the performance of a process.

3.4 erroneous laboratory results

In Six Sigma, the defects out of 1 million will be?

White belt

Basic or introductory level to Six Sigma

Yellow Belt

The Yellow Belt has learned already the specifics of Six Sigma and how it is being applied to the workplace.

Green Belt

• They have advanced analysis and resolution of the problem.

• They know how to solve the problem.

• They are the managers and oversee the team.

• They lead and manage projects while providing support to their superiors.

Black Belt

• The supervisor.

• Known as the agents of change.

• Expert already in the Six Sigma philosophy and principles.

• To mentor the yellow and the green belts

Master

• A master black belt trains the black belt.

• Undergone years and years of training.

• Training in many performance improvement methodologies.

• They have many years of leadership experience and also project management experience.

• The master black belt will provide support to the champion

Champion

• High-level executive.

• A division leader or a director who is responsible for overall quality in an organization.

• Highly paid.

• Years of training will also give them validation for promotion.

• Promotion to a higher level until they become executive-level.

• They are very important at the beginning of a Six Sigma implementation when changes are most likely to arise.

Sigma Metric

Is a value that expresses the variation in performance of a measurement procedure relative to the allowable variability in results to be suitable for medical decisions expressed in SD units

DPMO

is a ratio of the number of defects (flaws) in 1 million opportunities when an item can contain more than 1 defect.