Quality Assurance in haematology. Internal & External Quality Assurance, Define accuracy, precision & Standard Deviation. UNIT IV IInd Semester DMLT.

“Quality assurance (QA) in the clinical laboratory is activities to ensure that hematology laboratory is providing a report with accuracy to the medical practitioner and patient.” Quality assurance ensures to provision of reliable and relevant data to medical practitioners, patient,s and laboratory staff. It brings faith to medical practitioners and patients in the report provided by the pathological laboratory.

Essentials of Quality Assurance

The following are essential elements of Quality Assurance in a clinical laboratory:

1. Quality Control (QC): QC involves the monitoring and verification of testing processes. It ensures performing as specified parameters. This includes regular calibration of equipment, verification of reagents, and monitoring of test results using control materials.

2. Standard Operating Procedures (SOPs): SOPs provide detailed instructions for all laboratory processes from specimen collection to result reporting. These procedures ensure uniformity in testing methodologies and reduce the risk of errors.

3. Personnel Training and Competency Assessment: Laboratory staff must undergo training and demonstrate competency in performing testing procedures. Training should cover technical skills, safety protocols, and adherence to regulatory requirements.

4. Quality Management System (QMS): A QMS manages quality throughout the laboratory. It includes processes for document control, corrective and preventive actions (CAPA), risk management, and proficiency testing.

5. External Quality Assessment (EQA): EQA programs involve the participation of external agencies in proficiency testing. These programs allow laboratories to improve their performance against peers. EQA identifies any systematic errors or biases in their testing processes.

6. Instrument and Equipment Maintenance: Regular maintenance and calibration of laboratory instruments and equipment are essential to ensure the accuracy of test results.

7. Document Control and Record Keeping: Proper documentation of all laboratory activities, including test results, instrument maintenance, training records, and corrective actions, is crucial for traceability, responsibility, and regulatory compliance.

8. Risk Management: Risk management involves identifying potential risks to quality, patient safety, and data integrity within the laboratory.Top of Form

Objectives of QA in clinical laboratory:

Quality assurance aims to establish

• 1. Accurate diagnosis of disease

• 2. Appropriate treatment of disease

• 3. Successful treatment of disease

• 4. Source of infection

• 5. Early diagnosis of outbreak of infection

• 6. Accurate, timely, and complete report.

Quality assurance can be achieved by focusing on internal quality assurance and external quality assurance.

INTERNAL QUALITY ASSURANCE:

It includes all measures to ensure that the results of laboratory instruments are correct and reproducible. It is carried out through a checklist to ensure the following

1. Machinery, equipment, and glassware maintenance:

• · All machinery, equipment, and glass wares are well-standardised and calibrated regularly.

• · Cheaped and cracked glass wares are not in use.

• · Glass wares are well-cleaned before and after their use.

• · Disposable equipment is not reused.

• · Daily and monthly schedules are followed to maintain all machinery, equipment, and glass wares.

• · A separate schedule maintenance sheet is maintained for all machinery, equipment, and glass wares.

• · Tolerance limit range is mentioned for all machinery, equipment, and glass wares.

• · Temperature of thermostatically controlled instruments such as autoclave, incubator, oven, hot plate, freezer, refrigerator, etc is recorded daily before their use.

2. Reagents, Standard and reference controls

• · The date of preparation of reagents and reagents kits are recorded on their containers and in the stock register,

• · The date of manufacturing of readymade reagents and reagents kits are mentioned on their label and packaging. These are also recorded in the stock register. Their receiving date is recorded on their label, packing, and stock register.

• · Reagents and reagent kites are procured from standard and reputed sources only.

• · Only certified reference materials are in use inside the laboratory.

3. Control materials: Physical and chemical properties of control materials closely resemble with specimen or sample.

• · Control materials are procured from certified sources.

• · Control materials may be prepared in the laboratory but they should be used only in emergencies.

• · Control materials should remain stable for a longer duration.

• · Control materials are tested similarly as specimens are tested.

• · Control materials are stored properly as per the recommendation on their label..

• · Freeze or refrigerated control materials are used when they attain their normal temperature.

4. Methods selection:

• · Well-established and documented methods are used to analyze and test the specimens.

• · New methods to analyze and test the samples are selected very carefully.

• · Managerial and technical factors are considered to selecting new methods. Managerial factors include instrument cost, trained staff availability, specimen, etc. Technical factors include sensitivity, specificity, linear range of inaccuracy, and imprecision.

• · Sensitivity of method and evaluation +is to give accurate positive results in the presence of disease in a patient. It means sensitive methods and evaluation detects even a small amount of the constituent in the specimen. The specificity of the method and evaluation is to give accurate negative results in the absence of disease in a patient. Linear range is a range of concentration

5. Method evaluation:

Methods are evaluated to determine imprecision, inaccuracy, and maximum error. The inability to produce the same result from the same specimen on repeated tests is called imprecision. The difference between measured value and true value is called inaccuracy.

Control of pr-analytical Variables under internal quality assurance

Pre-analytical variables are factors that can influence the quality of a specimen before it undergoes testing. Addressing these variables involves implementing standardized procedures and best practices during specimen collection, handling, transportation, and processing, training personnel, etc. Laboratories can minimize the impact of pre-analytical variables on test outcomes and provide high-quality diagnostic services for patient care by controlling pre-analytical variables in clinical laboratories.

The following are the main aspects of controlling pre-analytical variables:

1. Specimen Collection: Proper specimen collection is the first step in controlling pre-analytical variables. This includes:

• · Correct identification of the patient and proper labeling of specimens.

• · Selection of the appropriate specimen type and collection container.

• · Specific protocols for sample collection.

• · Ensuring adequate sample volume to perform all required tests.

2. Specimen Handling and Transportation: Specimens must be handled and transported with care to maintain their integrity. This involves:

• · Proper labeling of specimens with patient name, collection date and time, and any other relevant information.

• · Storage and transportation of specimens at the appropriate temperature conditions to prevent degradation.

• · Use of suitable packaging materials and transportation methods to minimize the risk of specimen leakage or damage during transit.

• · Timely delivery of specimens to the laboratory to minimize delays in processing.

3. Specimen Processing: Pre-analytical variables are also be introduced during specimen processing steps. It is essential to:

• · Process specimens promptly upon receipt to prevent clot formation, hemolysis, or other changes.

• · Centrifuge specimens according to established protocols to separate serum or plasma from cellular components.

• · Aliquot specimens into appropriate containers for storage or further analysis. It ensures proper labeling and tracking of aliquots.

• · Document any deviations from standard processing procedures and take appropriate corrective actions.

4. Quality Assurance Measures: Implementing quality assurance measures control pre-analytical variables. This includes:

• · Regular training and assessment of personnel involved in specimen collection, handling, and processing.

• · Use of standardized protocols and procedures for specimen management.

• · Monitoring and documentation of pre-analytical errors to identify trends and areas for improvement.

• · Participation in external quality assessment programs to benchmark pre-analytical processes against peer laboratories.

5. Patient Preparation and Instructions: Providing clear instructions to patients before specimen collection minimizes pre-analytical variables. This includes:

• · Communicating fasting requirements or dietary restrictions for tests.

• · Advising patients on proper specimen collection procedures, such as urine collection techniques.

• · Guiding medications or substances to avoid before testing.Top of Form

Control of analytical Variables under internal quality assurance.

Control of analytical variables in clinical laboratories ensures the accuracy, precision, and reliability of test results. Analytical variables influence the outcome of laboratory tests, including equipment performance, reagent quality, environmental conditions, and operator proficiency. The following are some aspects of controlling analytical variables in clinical laboratories:

1. Calibration and Maintenance of Equipment: Regular calibration and maintenance of laboratory instruments and equipment are essential to ensure accurate test results. Calibration involves adjusting instruments to ensure accuracy.

2. Quality Control (QC) Procedures: QC procedures involve the use of control materials (Reference materials). Reference control has known values. It monitors the accuracy and precision of testing methods.

3. Reagent Quality Control: Reagents used in laboratory tests must meet specified quality standards to ensure accurate and reliable results. This includes proper storage, handling, and verification of reagent integrity before use.

4. Environmental Monitoring: Environmental conditions such as temperature, humidity, and light impact the performance of laboratory tests. Laboratories should monitor and control these variables to minimize their impact on test results.

5. Operator Training and Proficiency: Proper training and ongoing competency assessment of laboratory personnel are essential. It ensures accurate test performance. This includes training on testing methodologies, instrument operation, and adherence to standard operating procedures (SOPs).

6. Internal Quality Control (IQC): IQC involves the use of control charts and statistical tools. It monitors the performance of analytical systems.

7. Risk Management: Risk management processes should be in place to identify sources of error or variability in testing processes.

EXTERNAL QUALITY CONTROL:

The comparison of internal quality with external sources is called external quality control. Samples are supplied to participating laboratories. External quality control is also called proficiency testing. Participating laboratories submit test reports within a specified period. Results are compared with the expected results.

DEFINE ACCURACY, PRECISION & STANDARD DEVIATION:

• · Accuracy: Accuracy is the degree of closeness between measured values and true values.

• · Closeness of two measured values is called the precision of the result. Precision is the degree of closeness of two or more results upon repeated tests of the specimens under the same condition.

• · Standard deviation is statistical data. Standard deviation is a measure to show variation from the mean value of data.

Dr Pramila Singh