Sensitivity: Proportion of those people who have the disease who are correctly detected by the test.
Specificity: Proportion of those people who do not have the disease who are correctly left undetected by the test.
Negative Predictive value: Proportion of those testing negative who are truly disease free.
Positive Predicative Value: Proportion of those testing positive who truly have the disease.
Diagnostic test: Test offered to people who have a specific indication of possible illness (a history, symptom, sign or screening test result) to determine whether or not they have the disease in question.
Screening test: Test offered to asymptomatic people who may or may not have early disease or disease precursor and are sued to guide whether or not a diagnostic test should be offered.
Parallel testing: screening tests performed at the same time and the results are subsequently combined.
Serial testing: Second screening test is performed only if the result of the first screening test is positive.
True positive test result: A person with the condition tested for, and a positive test result.
False positive test result: A person without the condition tested for, and a positive test result.
True negative test result: A person without the condition tested for, and a negative test result.
False negative test result: A person with the condition tested for, and a negative test result.
Receiver operating characteristic (ROC): Is a plot of sensitivity versus 1- specificity.
Inter-rater reliability: is the degree of agreement among raters of the result of a diagnostic test. If there is significant disagreement of a test outcome between raters, either the scale is defective or better training needs to be provided for those who use the test.
Test-retest reliability. Is used to determine a test's reliability. A diagnostic test on the same person in short succession should provide the same test result. However, the same test result on the same person over a long period may result from a test's inability to detect subtle changes.
Prevalence of a disease: Proportion of a population with a disease.
