L1 - Quality Assurance Flashcards
What are the three general sources of error in biochemical analysis based on time-scale?
At what stages in the process of analysis do these occur?
Pre-analytical - before sample gets to the lab
Analytical - during analysis
Post-analytical - what happens to the results
Give three sources of pre-analytical errors
Poor sampling technique, inappropriate containers, storage or transport, not enough sample, errors in patient ID
How can pre-analytical errors be minimised?
Training staff who are to be taking samples, get receptionists to check samples, use barcodes to prevent errors in patient ID
Give three sources of analytical errors
Poor precision/random errors, poor accuracy/systematic errors, poor quality assurance
How can analytical errors be minimised?
Automation, method validation, quality procedures
Give three sources of post-analytical errors
Errors in collation or recording of results, inappropriate reference ranges
Define accuracy
Ability to measure the true value
Define precision
Ability to produce consistent results
Define sensitivity
Ability to identify those with a condition (fewer false-negatives)
Define specificity
Ability to exclude those without a condition (fewer false-positives)
Define analytical sensitivity
Smallest amount of analyte a test can distinguish from zero
Define analytical specificity
Ability to measure only the analyte in question
What are the two types of error in biochemical analysis?
Systematic error and random error
Define systematic error
Are these precise or accurate?
Values are systematically too high OR too low
Precise
Define random error
Are these precise or accurate?
Results are scattered
Accurate
