Result Inerpretation And Reference Intervals Flashcards
Define: Reference Intervals
Reference intervals (or reference ranges) are the range of values that are expected for a particular laboratory test in a healthy population, used as a basis for comparison when interpreting test results for individuals. ¿˘¯ÆÚ”’±—‚·°‡°°°°°‡flfiflflflflfi›‹™™⁄ŸŸ„‰ÊÁÈ∏ØÈËÁʉÚÒÔÓÌÏÎÍÅÓÌÔÓ˘¯˜ˆı◊ÇÙÛ…¬˚∆˙©ƒ∂ßåç√ç≈ΩΩΩåß∂ß∂∂∂ßßßßßßßßß߃ƒƒƒ©©©˙˙˙˙∆∆∆∆˚˚˚¬¬¬¬…ææææææ÷÷≥≤µ~∫√ç≈Ω
Define: decision limits
Decision limits are predetermined values used to aid in the interpretation of a laboratory test, usually based on clinical criteria or disease thresholds.
How is a reference interval in a given population established?
The reference interval can be established by collecting samples from a group of healthy individuals.
The samples should be collected under controlled conditions, and the individuals should be representative of the population for which the reference interval is being established.
The samples should be analyzed using the same methods that will be used for patient samples, and the reference interval should be determined statistically.
What are pre-analytical factors?
Sample collection
Handling
Transportation
What are analytical factors? (3)
Instrument variation
Reagent stability
Operator variability
Biological Factors
Individual variation in metabolism or disease state
What is precision?
Reproducibility of a test result
What is accuracy?
How closely the test result corresponds to the true value
What is the limit of detection?
Lowest concentration of analyte that can be reliably tested by the test method
What is sensitivity?
The proportion of true positive results for a particular condition
What is specificity?
The proportion of true negative results for a particular condition.
Internal quality control
Internal quality control refers to the processes that ensure that each individual test is accurate and precise.
This includes the use of controls, calibration, and regular maintenance of equipment.
External quality control
External quality assurance refers to the processes that ensure that the laboratory’s testing processes are accurate and precise over time.
This includes participation in proficiency testing programs, where samples are provided by an external organization and the laboratory’s results are compared to those of other laboratories.
