2- QUALITY CONTROL Flashcards
o In business, it can mean conformance to the
requirements of the users/customers
o In laboratory, can mean patient satisfaction
Quality
A complete system of creating and following
procedures and policies
To aim for providing the most reliable patient
laboratory results, and
To minimize errors in the pre-analytical, analytical, and postanalytical phases
Three phases
Quality Assurance (QA)
o Covers all standard operating procedures (SOP) that aims to provide the most reliable patient results and at the same time that aims to reduce errors that may occur in the laboratory, considering the three (3)
phases of testing process
Quality Assurance (QA)
o Falls under quality assurance
o Under the umbrella of a larger system, which is quality assurance
o A system of ensuring accuracy and precision in the laboratory by using quality control materials in every series of measurement
Quality Control (QC)
In QC, the materials being utilized for quality control purposes are called
Quality Control Materials
The materials being used for the sole purpose of calibrating machines/equipment in laboratory are called
Reference Materials
Refers to the overall process used to ensure that laboratory results meet the requirements for health care services to patients
Total Quality Management (TQM)
covers all procedures necessary to ensure
that quality health services are received by our
patients
Total Quality Management (TQM)
QMS Components
o Documents and records of the patients
o Organization of the laboratory
o Personnel who work in the laboratory
o Equipment/Analyzer we utilize for laboratory
testing
o Purchasing and inventory of supplies or
equipment
o Process control
o Information management
o Occurrence management
o Assessment
o Process improvement
o Service and satisfaction
o Facilities and safety
Components under process control (Analytical)
Calibration
Maintenance procedures
Quality Control
PT (Proficiency testing)/EQA (External
Quality Assurance)
using standards or standard solution
Calibration
troubleshooting mechanism you need to perform in the laboratory should your analyzer failed to release results within the control limits
Maintenance procedures
are intervals of acceptable values with upper
and lower limits
Control limits
Ideal control limit is?
+/- 2SD
The principle of analyzing QC in the laboratory were applied in 1950s by
Levey and Jennings
Most commonly used quality control chart in the laboratory
Levey and Jennings chart
are specimens analyzed for QC purposes
QC materials (control solutions)
sample from a total volume of the
control solution
Aliquot
Or if you are going to get an aliquot of a control solution, that aliquot should be
stable for extended period of time
if you are performing laboratory test using a serum sample, then the quality control material must be prepared using a ____________ this is called as _________
serum sample too
Same Matrix
Most commercially prepared QC materials are
lyophilized
This means they come in pulverized or powdered form so that reconstitution is needed
lyophilized
This means you have to add the necessary
diluent to come up with a homogenous mixture of the control solution
Reconstitution
QC for general chemistry to assays uses
2 level of control
Level 1 control is
Normal control
Level 2 control is
Abnormal control
contains concentrations which are outside the control limit of the analyte being tested (lower than the lower limit or higher than the higher limit)
Abnormal control
Immunoassays commonly use how many levels of controls, and what are these controls
3:
1- Low control
2- Normal control
3- High control
OBJECTIVES OF QUALITY CONTROL
To check the stability of the machine
To check the quality of the reagents
To check technical (operator) errors
refers to the errors that we encounter in the laboratory considering the three phases of testing process
Variation (in CC lab)
When exceeded statistical limit of variations and have done the corrective action, the next thing to do is
reject the run
If error exceeded statistical limit of variations &
have done the necessary corrective actions, QC
results are within the control limits, then
accept the run
KINDS OF QUALITY CONTROL
Intralab Quality Control (Internal QC)
Interlab Quality Control (External QC)
NEQAS (National External Quality Assurance Scheme)
Kind of quality control that Involves the analyses of control samples and the patient specimen; use for the daily monitoring of accuracy and precision of analytical methods
Intralab Quality Control (Internal QC)
Kind of quality control that Involves proficiency testing programs that periodically provide samples of unknown considerations to participating laboratories; important in maintaining long-term accuracy of analytical methods
Interlab Quality Control (External QC)
gold standards for clinical laboratory
external QC testing
College of American Pathologists (CAP) proficiency program
is our External QC testing (PH)
NEQAS (National External Quality Assurance
Scheme)
Parasitology NEQAS
Research Institute for Tropical Medicine (RITM)
Immunology/Serology NEQAS
San Lazaro Hospital /STD-AODS Cooperative Central
Laboratory (SLH/SACCL)
Hematology NEQAS
National Kidney and Transplant Institute (NKTI)
Clinical Chemistry NEQAS
Lung Center of the Philippines (LCP)
Toxicology, Occupational and Environmental
Health and Micronutrient Assay NEQAS
East Avenue Medical Center (EAMC)
What if all analytes tested are outside the
control limits for NEQAS
Laboratory can be a candidate for closure
10 analytes being quantified for NEQAS Clinical
Chemistry
Glucose
Blood Urea Nitrogen (BUN)
Creatinine
Uric Acid
Cholesterol
Triglycerides
Albumin
Sodium
Potassium
Chloride
– ability of the analytical method/process to
detect the smallest concentration of analyte of interest
Sensitivity
– measures only the analyte of interest
Specificity
closeness or nearness of the results to
the true or target value
Accuracy
closeness of the results to the repeated
value
Precision
The magnitude of change is constant and not
dependent on amount of analyte
o Cause: interference or contaminatio
Constant Error
o Error dependent on analyte concentration
o Cause: poor recovery of analyte during an analysis
Proportional Error (Slope/Recent Error)
Present in all measurements; due to chance
Random Error
Error always in one direction
Systematic Error
It is the most widely used QC chart in the clinical laboratory
SHEWHART LEVEY – JENNINGS CHART
gives earliest indication of
systematic errors
Cumulative Sum Graph
used to determine proportional/ constant errors
Youden / Twin plot
