WEEK 2: Workshop: Screening Programmes Flashcards
What is screening?
It is the application of a test or procedure to asymptomatic people in order to detect disease early.
Screening classifies people into 2 groups. State them.
It classifies people into 2 groups:
*One at high risk of developing clinical disease
*The other at low risk of developing it.
What is the aim of screening?
*To detect disease early, before it becomes clinically apparent, and treat it
State the 3 Assumptions in Screening
- Early detection before the development of symptoms means a better prognosis
- Treatment - effective, acceptable and available
- Relies on screening tests
State the Benefits of Screening.
■ Early disease identification in the community
■ Results in early intervention (prevention or control)
■ Hopes to reduce disease morbidity or/and mortality
Differentiate Screening vs Diagnosis.
■ In screening, the patient being screened is asymptomatic and at apparently low risk of the disease being screened for
■ In diagnosis, the patient has symptoms or signs indicating a high likelihood of the disease being tested for
Differentiate between screening and diagnostic tests. (6)
Screening Test
■ Done on apparently healthy individuals
■ Applied to groups
■ Based on one criteria & cutoff
■ Less accurate
■ Less expensive
■ Not a basis for treatment
Diagnostic test
■ Done on sick or ill individuals
■ Applied on single patients
■ Based on evaluation of signs/symptoms & lab findings
■ More accurate
■ More expensive
■ Used as basis for treatment
Which of the following are screening tests?
■ Urine dipstick
■ Viral Load in HIV
■ CD4 Count in HIV
■ Random blood glucose
■ Fasting blood glucose
■ Mammogram
■ Renal biopsy
■ PAP SMEAR
■ COVID TEST- PCR
■ DIGITAL RECTAL EXAM (DRE)
Screening Tests:
*Urine dipstick
*Viral Load in HIV
*CD4 Count in HIV
*Random blood glucose
*Fasting blood glucose
*Mammogram
■ PAP SMEAR
■ COVID TEST- PCR
■ DIGITAL RECTAL EXAM (DRE)
Non-Screening Test:
*Renal biopsy
State the Principles of Screening. What is considered?
■ The choice of disease for which to screen
■ The nature of the screening test
■ The availability of a treatment for the disease
■ The relative costs of the screening
What elements of the disease are considered?
The Disease
■ The condition should be an important public health problem
■ There should be a recognizable latent or early symptomatic phase
■ The natural history of the disease should be adequately known & understood
What is the natural history of a disease?
The natural history of a disease refers to the course or progression of a medical condition in the absence of treatment.
It outlines the typical development of the disease over time, from the initial exposure or onset of the disease to its resolution, chronicity, or death.
State the principles of the test which are considered.
■ There should be an appropriate test available for detection of the disease
■ The screening test should be valid, reliable, with acceptable yield
■ The test should be acceptable to the population
What principles of the treatment should be considered.
■ There should be an effective treatment available for the disease
■ There should be adequate facilities for diagnosis and treatment of the disease
■ There should be an agreed policy on who to treat
State the principles of cost which are considered.
■ The cost of case-finding (including a diagnosis and treatment of patients diagnosed) should be economically balanced in relation to possible
expenditure on medical care as a whole
■ Case finding should be a continuing process and not a “once off” project
State the Criteria for evaluating a screening test.
■ Validity (accuracy): How close is the result of a test to its true value (sensitivity & specificity)
■ Yield: Amount of disease detected in the population, relative to the effort
■ Reliability (precision): How close are the results of a test on repetition