| Question |
Answer |
| Testing |
done on those suspected on basis of signs, symptoms or family history to have disease |
| Screening |
done independent of signs, symptoms, or family history |
| mass screening |
low false negative rate; follow-ups identify true positives and true negatives, inexpensive |
| Sensitivity |
A/A+C percentage of affected actually affected |
| Specificity |
D/B+D percentage of unaffected who are unaffected |
| To confirm results that may be false positives |
confirm for genetic heterogeneity, biologic variation, error |
| Biochemical assays |
comprehensive in covering multiple mutations in one gene or several genes in a metabolic pathway with a common endpoint |
| DNA mutation screens |
Requires high frequency mutations with current technology |
| A primary goal of population screening is |
to predict with high accuracy which individuals in a group are at significant risk of developing or transmitting a disease. |
| Once individuals at high risk for a disease are identified |
confirmatory (diagnostic) tests are then performed to detect the screened-for disease with greater certainty |
| A screening test only indicates |
who in a given population is most likely to be at higher risk for developing a disease. |
| A false positive occurs when a test |
misidentifies individuals as being higher risk, when they are actually not at higher risk. |
| A false negative occurs when |
individuals with a higher risk for the disorder are not identified by the screening test. |
| a diagnostic test is done following a positive screening test to determine |
whether an individual has a disorder and thus rules out false positives. Diagnostic tests are typically more |
| Disease registries |
a valuable epidemiological resource that can be used to calculate incidence rates and risks, as well as to maintain surveillance and monitor trends in incidence and mortality. |
Ch.18 LTI-MA 509
