Untitled Quiz

Quality Control

• A system for ensuring accuracy and precision in laboratory measurements, including quality control reagents in every series of measurements.
• Process to ensure analytical results are correct by testing known samples.
• Monitors analytical processes and detects errors.
• Assesses the "health" of an analytical method.

Quality Control Parameters

• Sensitivity
• Specificity
• Accuracy
• Precision/Reproducibility
• Practicability
• Reliability
• Diagnostic sensitivity
• Diagnostic specificity

Quality Control Types

• Built-in Controls: Integrated into test kits; used to confirm that diluents and active ingredients are functional, but not a confirmation of sample application or kit performance. Validates kit performance, not the entire testing process.
• Traditional Controls: Mimics patient samples, to evaluate the integrity of the entire testing process. Often included within a testing kit. Can also be commercially prepared.

Intralab (Internal QC)

• Involves analyzing control samples alongside patient samples.
• Monitors accuracy and precision of analytical methods.
• Detects random and systematic errors.

Interlab (External QC)

• Proficiency testing program using samples of unknown concentrations.
• Maintains long-term accuracy of analytical methods.

Sources of Quality Control

• Human-based
• Bovine-based

Objectives of Quality Control

• Validating the reliability of the test system
• Verifying instrument and reagent conditions
• Evaluating operator performance
• Assessing environmental conditions impacting results
• Checking machine and reagent stability.
• Detecting and monitoring any technical errors

Ideal QC Material Characteristics

• Resembles human samples
• Inexpensive and stable for extended periods
• Free of communicable diseases
• No matrix effects (sample interference)
• Known analyte concentration
• Convenient and easy dispensing/storage

Coefficient of Variation (CV)

• The standard deviation expressed as a percentage of the mean.
• Used to monitor precision.
• Used to compare methods.
• Ideally should be less than 5%.

Analytical Variations/Errors

• Systematic Error: Predictable errors, occurring in a pattern.
• Random Error: Unpredictable, imprecise errors, based on imprecision.

Random Error Types

• Mislabeling
• Pipetting errors
• Improper mixing of sample and reagents
• Voltage fluctuations
• Temperature fluctuations
• Dirty optics

Systematic Error Types

• Improper calibration
• Deterioration (of reagents)
• Contamination (of solutions)
• Sample instability (unstable reagent blanks)
• Changes in standard materials
• Broken ion selective electrodes
• Low lamp power
• Incorrect instrument settings
• Incorrect sample and reagent volume
• Procedure errors

Quantitative Control Chart

• Plots control material values, calculated mean and +/- 1, 2, and 3 standard deviations (SD).

Quality Control Chart

• Gaussian Curve (Bell-Shaped Curve): Data is centered around the mean, with most elements close to the mean (accuracy). A shift in the mean indicates an accuracy problem, while increased SD points to a precision problem.
• Shewhart Levey-Jennings Chart: Commonly used chart for continuous monitoring and detecting patterns or errors in analytical processes.
• Control Rules: Standards for ruling out any irregularities. Includes 13s, 22s and 41s, these rules detect random and systematic errors.
• Youden Plot: Compares results from high and low control sera, from different laboratories. Detects problems in different labs operating conditions.

Standard Deviation (SD)

• Measure of variability used in the laboratory.

Delta Check

• Used to compare present results with past results.

Interference and Recovery Experiments

• Used to measure systematic errors or inaccuracies in an assay.

Point of Care Testing (POCT)

• Analytical tests performed outside the laboratory, typically by non-laboratory personnel.
• Examples include blood glucose meters.

Analytical Techniques and Instrumentation

• Photometry: Measures the absorbance or transmission of light through a sample.
• Spectrophotometry Single beam and double beam types Using light of selected wavelength Components: Source of light, monochrometer (isolates specific wavelengths), cuvette for sample, and detector(converts light to electrical energy).
• Spectrophotometry: The quantitative measure of light absorbed or transmitted by a sample dissolved in a solution.

Quality Control (QC) Chart Elements

• Gaussian Curve (Bell-Shaped Curve): Data elements are centered around the mean; elements close-to the mean -accuracy.
• Deviation (SD): Increased SD -precision problem.
• Mean/ Average: Increased or decreased mean-accuracy problem.
• Rules: 13s, 22s, 41s, R4s, and 10x.

Other Analytical Methods

• Turbidimetry: Measures the reduction in light transmission caused by particles in the liquid sample;
• Nephelometry: Measures the scattering of light by particles in a liquid sample.
• Chemiluminescence: Measures the light emitted from a chemical reaction.

General/Clinical Chemistry

• Cuolometry: Measurement of the amount of electricity in coulombs at a fixed potential.
• Voltammetry: Measurement of current at varying potential.
• Electrophoresis: Separates charged molecules in an electrical field, based on size and charge.
• Chromatography: Separates complex mixtures based on interactions between individual compounds and the stationary phase of the system.
  • Gas Chromatography
  • High-Performance Liquid Chromatography (HPLC)

Other Methods (e.g., Capillary Electrophoresis, Mass Spectrometry)

• Briefly described

Specimen Collection and Handling

• Describe common specimen collection practices (e.g., blood draws), preparation, and handling details.

Patient Preparation

• Describe factors affecting test results (e.g., exercise, fasting, posture).

Capillary Puncture (Skin Puncture)

• Discuss the procedure, considerations and precautions.

Anticoagulants

• Types (e.g., oxalate, citrate, EDTA), their roles (e.g., combine with Calcium).

Other important elements (osmometry, hormones)

• Described briefly, and other important aspects of clinical chemistry.

Automated Testing

• Approaches (e.g., Continuous Flow, Centrifugal),
• Terminologies (e.g., sequential testing, batch testing).

Other tests and procedures

• Describe different types of blood tests, urine tests, and other relevant methods.

Reference Ranges

• Provide reference values for specific components/tests.

Diseases

• Describe conditions/diseases related to the mentioned elements and procedures.