Screening Yield Explained
Screening efforts aim to detect diseases in individuals who might not yet show symptoms or know they are affected. The key is identifying previously unrecognized disease.
Defining Screening Yield
The term specifically used for the amount of previously unrecognized disease that is discovered or diagnosed as a direct result of a screening program is called Yield.
- Yield: Represents the number or proportion of individuals found to have the target disease through the screening process. It directly measures the diagnostic outcome of the screening effort itself.
Understanding Other Terms
It's important to distinguish Yield from related concepts:
- Predictive accuracy: Refers to how well a screening test predicts the presence or absence of the disease in the future or at the time of testing (e.g., positive predictive value, negative predictive value).
- Reliability: Concerns the consistency and repeatability of the screening test results. A reliable test gives similar results under consistent conditions.
- Validity: Assesses how accurately the screening test measures the condition it is intended to measure. It relates to the test's true accuracy (sensitivity and specificity).
Therefore, the amount of previously unrecognized disease diagnosed via screening is known as the screening program's Yield.
Important Questions from General Epidemiology
Which of the following statements are correct for incidence rate?
1. It is useful for taking action to control a disease.
2. Rising incidence rates may indicate ineffectiveness of the current control programmes.
3. Fluctuation in incidence rate may indicate a change in aetiology of disease.
Select the answer using the code given below.
Consider the following definition :
"A high level of infection beginning early in life and affecting most of the child population, leading to a state of equilibrium such that the adult population shows evidence of the disease much less commonly than the children."
Which one of the following terms best fits this definition?
- In which one of the following study designs, the unit of study involves populations rather than individuals ?
- Which one of the following best explains the relationship among Prevalence (P), Incidence (I) and Duration (D) of a disease given the assumption that the population is stable?
- Which one of the following is a famous large prospective study that helped establish risk factors for coronary heart disease?
