What are reference values?
a set of values from a group of healthy animals (minimum 40 animals) that provides a basis for comparison with results from animals undergoing tests
What are the steps in determining reference values?
selecting healthy animals using precise inclusion and exclusion criteria, determine individual values and apply appropriate statistical tests to describe set of values obtained and determine limits of the reference values
What are the lower and upper limits of a reference interval?
What do conventional units tell?
the mass concentration (the mass of the solute/unit of volume of solution) - used in the U.S.
What do SI units tell?
substance concentration (number of moles/unit volume of solution) - used by the rest of the world
With medical decision making, what three factors must be considered?
clinical history, physical examination and laboratory/other results
What is sensitivity?
the % of true-positive results in the diseased group
What is specificity?
the % of true negative results in the non-diseased group
What is efficiency of a test?
% of patients correctly classified
How can test efficiency be improved?
by increasing the sensitivity and specificity of a test