Define the normal range
reference range
defines the values of biochemical test found in healthy subjects against which patient values can be compared
what is specificity
Specificity (also called the true negative rate) measures the proportion of negatives that are correctly identified as such (e.g., the percentage of healthy people who are correctly identified as not having the condition).
what is sensitivity
Sensitivity refers to the test’s ability to correctly detect patients who do have the condition
e.g., the percentage of sick people who are correctly identified as having the condition (positives) eg screening test