Screening Tests Overview
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Questions and Answers

What is screening motivated by?

The potential benefits of secondary prevention through early detection and treatment.

What is screening?

The process of using tests on a large scale to identify the presence of disease in people who appear healthy.

Screening tests usually establish a diagnosis.

False (B)

What is the aim of screening?

<p>To search for unrecognized disease or defect by means of rapidly applied tests, examination or other procedures in apparently healthy individuals.</p> Signup and view all the answers

A screening test should be likely to cause harm.

<p>False (B)</p> Signup and view all the answers

Screening can be used to identify exposure to risk factors.

<p>True (A)</p> Signup and view all the answers

Which of these is a type of screening?

<p>All of the above (D)</p> Signup and view all the answers

What is the goal of mass screening?

<p>To screen the whole population or a subset of it.</p> Signup and view all the answers

What is multiple or multiphasic screening?

<p>It uses several screening tests at the same time.</p> Signup and view all the answers

What is targeted screening directed at?

<p>Groups with specific exposure to risk factors.</p> Signup and view all the answers

What is the aim of case-finding or opportunistic screening?

<p>To identify patients who consult a health practitioner for other purposes.</p> Signup and view all the answers

What is the purpose of mass screening?

<p>To apply a screening test to a large, unselected population.</p> Signup and view all the answers

Give an example of an application of mass screening.

<p>Visual defects in school children.</p> Signup and view all the answers

What is the primary use of mass screening?

<p>Mass screening is not helpful for preventive measures but it is helpful for a suitable treatment that will reduce the duration of illness or alter its final outcome.</p> Signup and view all the answers

What is multipurpose screening?

<p>The screening of a population by more than one test done simultaneously to detect more than one disease</p> Signup and view all the answers

Give an example of an application of multipurpose screening.

<p>Screening of pregnant women for VDRL, HIV, HBV by serological tests</p> Signup and view all the answers

What is multiphasic screening?

<p>It involves various diagnostic procedures employed during the same screening program.</p> Signup and view all the answers

Give an example of an application of multiphasic screening.

<p>DM-FBS, Glucose tolerance test and Sickle cell anemia-CBC,HB electrophoresis.</p> Signup and view all the answers

Multiphasic screening is considered more accurate due to the use of numerous tests to diagnose a specific condition.

<p>True (A)</p> Signup and view all the answers

What is targeted screening?

<p>The screening of selected high-risk groups in the population.</p> Signup and view all the answers

Give an example of an application of targeted screening.

<p>Screening fetus for Down's Syndrome in a mother who already has child with Down's Syndrome.</p> Signup and view all the answers

What are some additional examples of targeted screening?

<p>Screening for familial cancers, HTN and DM.</p> Signup and view all the answers

What is case-finding or opportunistic screening directed at?

<p>Patients who consult a health practitioner for other purposes.</p> Signup and view all the answers

There is always an accurate and precise diagnostic test available for every disease.

<p>False (B)</p> Signup and view all the answers

What is the main objective of case-finding screening?

<p>To detect disease and bring patients to treatment.</p> Signup and view all the answers

Give an example of an application of case-finding screening.

<p>RHD in children.</p> Signup and view all the answers

What are the uses of screening?

<p>All of the above (E)</p> Signup and view all the answers

What does prescriptive screening involve?

<p>People are screened for their own benefit.</p> Signup and view all the answers

Give examples of prescriptive screening.

<p>Cancer, DM, and HTN.</p> Signup and view all the answers

How can screening be utilized in research?

<p>It can help researchers understand the natural history of a disease.</p> Signup and view all the answers

What are the educational purposes of screening?

<p>It can raise public awareness about specific diseases and the importance of early detection.</p> Signup and view all the answers

What are essential characteristics of an ideal screening test?

<p>It should be cheap, easy to apply, acceptable to the public, reliable and valid.</p> Signup and view all the answers

A screening test is considered valid if it accurately categorizes individuals into groups with and without disease.

<p>True (A)</p> Signup and view all the answers

A screening test is considered reliable if it provides inconsistent results.

<p>False (B)</p> Signup and view all the answers

What are the key measures of validity in a screening test?

<p>All of the above (D)</p> Signup and view all the answers

What does sensitivity refer to?

<p>A test's ability to identify all individuals with a disease correctly.</p> Signup and view all the answers

How is predictive accuracy determined?

<p>By predictive value.</p> Signup and view all the answers

Positive predictive value refers to the probability that an individual with a positive test result actually has the disease.

<p>True (A)</p> Signup and view all the answers

Negative predictive value refers to the probability that an individual with a negative test result does not have the disease.

<p>True (A)</p> Signup and view all the answers

What is the primary objective in a clinical situation?

<p>To diagnose any treatable disease.</p> Signup and view all the answers

What is the purpose of diagnostic testing?

<p>To help confirm possible diagnoses suggested by the patient's signs and symptoms.</p> Signup and view all the answers

Diagnostic tests often involve laboratory investigations.

<p>True (A)</p> Signup and view all the answers

What distinguishes diagnostic testing from screening tests?

<p>Diagnostic tests are applied to sick individuals to differentiate among likely diseases, while screening tests are applied to healthy populations to seek unrecognized disease.</p> Signup and view all the answers

What is surveillance?

<p>It is the ongoing, systematic collection, analysis, and interpretation of health data essential to the planning, implementation, and evaluation of public health practice.</p> Signup and view all the answers

What is the key purpose of public health surveillance?

<p>It provides 'information for action' to guide public health responses.</p> Signup and view all the answers

Surveillance data is only used to identify new syndromes.

<p>False (B)</p> Signup and view all the answers

What are different types of surveillance?

<p>All of the above (E)</p> Signup and view all the answers

How is passive surveillance carried out?

<p>Local and state health departments rely on health care providers or laboratories to report cases of disease.</p> Signup and view all the answers

What is the key advantage of passive surveillance?

<p>Its efficiency, as it requires relatively few resources.</p> Signup and view all the answers

What is a potential disadvantage of passive surveillance?

<p>Underreporting can result in incomplete data.</p> Signup and view all the answers

The majority of public health surveillance systems are passive.

<p>True (A)</p> Signup and view all the answers

How does active surveillance function?

<p>Health departments directly contact healthcare providers or laboratories requesting information about specific conditions or diseases to identify possible cases.</p> Signup and view all the answers

Active surveillance requires fewer resources than passive surveillance.

<p>False (B)</p> Signup and view all the answers

When is active surveillance particularly useful?

<p>When it is crucial to identify all cases of a specific disease or condition.</p> Signup and view all the answers

What is the focus of sentinel surveillance?

<p>It focuses on data from a certain subgroup rather than the whole population.</p> Signup and view all the answers

Give an example of an application of sentinel surveillance.

<p>Collecting data from hospitals.</p> Signup and view all the answers

What is the main focus of scanning surveillance?

<p>It focuses on data of clinical syndromes occurring before complete progression to disease status, or signs and symptoms occurring prior to diagnosis of disease.</p> Signup and view all the answers

Give an example of syndromes often monitored under scanning surveillance.

<p>Influenza-like illness (ILI) and acute flaccid paralysis (AFP).</p> Signup and view all the answers

What is the purpose of scanning surveillance?

<p>It triggers more detailed investigation to explore the likelihood of new disease occurrence.</p> Signup and view all the answers

What is scanning surveillance also known as?

<p>Syndromic surveillance.</p> Signup and view all the answers

Scanning surveillance is more expensive and slower than systems that require laboratory confirmation.

<p>False (B)</p> Signup and view all the answers

What are the potential sources of data for surveillance?

<p>Mortality data, morbidity data, data for epidemic detection, data for laboratory surveillance, data for analyzing disease occurrence and risk factors, data for healthcare and health system surveillance, and environmental data.</p> Signup and view all the answers

Study Notes

Screening Tests

  • Screening for diseases, or risk factors predicting diseases, utilizes tests on a large scale to detect disease in seemingly healthy individuals.
  • This is done to facilitate early detection and treatment, a component of secondary prevention.
  • Screening tests typically assess risk factors rather than establish a firm diagnosis, requiring follow-up and treatment tailored to each individual.

Types of Screening

  • Mass Screening: Targets the entire population (or a subset), regardless of individual risk. Examples include visual defects in schoolchildren, mammograms for women under 40, and newborn screenings. Mass screening is useful for early treatment to reduce the duration or severity of an illness.
  • Multipurpose/Multiphasic Screening: Involves using several tests simultaneously to detect multiple diseases. An example is screening pregnant women for VDRL, HIV, and HBV using serological tests.
  • Targeted Screening: Focuses on specific high-risk groups, increasing the probability of identifying cases. Examples include screening pregnant women for Down syndrome in high-risk cases, cancers with a family history, and hypertension and diabetes.
  • Case-finding/Opportunistic Screening: Identifies diseases in patients already seeking healthcare for other reasons. Testing for Rhesus disease (RHD) in children is an example.

Criteria for Choosing Screening Tests

  • Significant Burden of Disease: The disease should significantly impact the population.
  • Detectable Preclinical Stage: The disease's early stages can be detected.
  • Well-Understood Disease History: The disease's progression is well understood.
  • Appropriate Test Availability: Valid, reliable, inexpensive tests for early disease detection.
  • Effective Treatment: Treatment options should be available for confirmed cases to benefit the disease outcome.
  • Appropriate Policy: A clear policy for the screening program.

Screening Tests: Characteristics

  • Inexpensive: Affordability is crucial.
  • Acceptable to the public: The test should not cause undue or unnecessary distress to the population.
  • Reliable: Produces consistent results.
  • Valid: Measures what it's intended to, separating people with and without disease accurately via specificity and sensitivity indicators.

Indicators for Validating Screening Tests

  • Sensitivity: Accuracy in identifying true cases among those with the disease.
  • Specificity: Accuracy in identifying those without the disease among those without the disease.
  • Predictive Value: The accuracy of positive or negative test results in predicting the presence or absence of a disease.

Screening Test Results

  • True Positives: Correctly identifying affected individuals.
  • False Positives: Healthy individuals incorrectly identified as sick.
  • True Negatives: Correctly identifying healthy individuals.
  • False Negatives: Affected individuals incorrectly identified as healthy.

Diagnostic Tests

  • Purpose: Confirms suspected diagnoses using laboratory investigation methods (genetic, microbiological, biochemical, physiological investigations).

Screening vs. Diagnosis

Feature Screening Diagnosis
Population Healthy individuals Individuals with symptoms
Goal Identify unrecognized disease Confirm/rule out a disease
Sensitivity High High
Specificity Less important High
Population size Often large Smaller
Cost Low Variable, often higher

Surveillance

  • Purpose: Ongoing collection, analysis, and interpretation of health data to inform, implement and evaluate public health practices with timely distribution to those who need the information.
  • Aims: Monitor disease trends; describe disease history; identify epidemics; monitor infectious agents; evaluate hypotheses; plan policy; and evaluate public health interventions.

Types of Surveillance

  • Passive Surveillance: Relying on health care providers/laboratories to report cases.
  • Active Surveillance: Health departments actively request information to identify possible cases.
  • Sentinel Surveillance: Focused on a specific subgroup to track disease patterns.
  • Scanning Surveillance: Quickly identifying cases before signs become prominent for early disease interventions.

Sources of Surveillance Data

  • Mortality Data: Death registries
  • Morbidity Data: Disease reports from routine services/individual case reports
  • Data for Detecting Epidemics: Data from field investigations, community-based surveillance, etc.

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Related Documents

Lecture 11: Screening Tests, Diagnostic Tests, and Surveillance Tests PDF

Description

This quiz explores the various types of screening tests used for early disease detection in healthy individuals. It covers mass screening, multipurpose screening, and targeted screening methods, highlighting their purposes and applications in secondary prevention. Test your knowledge on how these methods facilitate timely treatment and illness management.

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