Interpreting Laboratory Tests Flashcards
What are qualitative results?
yes/ no
What are semiquantitative results?
Negative (0)
Positive (1,2,3)
What are quantitative tests?
actual values:
units
amounts
concentrations
reaction rates
What is accuracy?
getting the right value
What is precision?
getting the same value every time
Where do we want “within run” and “without run” results to be?
within 5% of each other
What is “within run” and “without run” ?
calibrate devices using series of measurements with controls/ known analytes
How far off from true value is acceptable for lab testing (reference range)?
within 95% of 2 standard deviations
What is a statistically derived numerical range obtained by testing a sample of individuals in the lab area?
reference range
What factors affect reference range?
analytical
small reference sample
random vs nonrandom
skewed distribution
healthy vs not healthy
physiological factors
What are critical values?
far enough outside reference range that it indicated impending morbidity
What is a high critical value?
2-3 x upper normal limit UNL
What is a low critical value?
no guideline; go off symptoms
What is the reliability of a test to determine a positive result?
sensitivity
What is the reliability of a test to detect a negative result?
specificity
