Screening of Diseases and Health Concepts MCQs

Community Medicine (PSM) · 130 free questions with answers & explanations.

1. A screening test for cervical cancer (VIA) has a sensitivity of 80% and specificity of 85%. In a population with 5% prevalence of disease, what is the positive predictive value (PPV)?
2. Which of the following is a requirement for a disease to be suitable for population-based screening?
3. A screening test for diabetes has sensitivity 80% and specificity 90%. In a population with 10% diabetes prevalence, the Positive Predictive Value (PPV) is approximately:
4. When two screening tests are applied in PARALLEL (simultaneously) for the same disease, the result compared to using either test alone is:
5. A test has sensitivity 90% and specificity 85%. The Likelihood Ratio of a Positive test (LR+) is:
6. Wilson and Jungner (1968) proposed classic criteria for a screening programme. Which of the following is NOT among their original 10 criteria?
7. A new cancer screening test is evaluated in a population. The Likelihood Ratio Positive (LR+) is 15 and Likelihood Ratio Negative (LR−) is 0.04. Which interpretation is correct?
8. A screening test for cervical cancer has a sensitivity of 80% and specificity of 90%. In a population with a disease prevalence of 1%, the Positive Predictive Value (PPV) of the test is approximately:
9. When comparing two screening tests applied sequentially (Test A then Test B), the strategy that maximizes sensitivity (misses fewest cases) is:
10. A population-based cervical cancer screening programme reports a reduction in cervical cancer mortality 5 years after introduction of VIA (Visual Inspection with Acetic acid) screening. A critic argues that this improvement may be due to 'length-biased sampling' rather than true benefit of the programme. Length-biased sampling means:
11. A screening test for cervical cancer has a sensitivity of 80% and specificity of 90%. In a population where the prevalence of cervical cancer is 1%, the Positive Predictive Value (PPV) of this test will be approximately:
12. Lead time bias in cancer screening programs causes:
13. A 45-year-old woman is tested for a breast lump. Test A has ROC-AUC = 0.92 and Test B has ROC-AUC = 0.65. The MOST appropriate interpretation is:
14. Wilson and Jungner's criteria for a good screening programme include all of the following EXCEPT:
15. A screening test for cervical cancer has a sensitivity of 80% and specificity of 90%. In a population of 10,000 women where the prevalence of cervical cancer is 2%, what is the Positive Predictive Value (PPV) of the test?
16. Lead-time bias in cancer screening studies artificially inflates survival time because:
17. Wilson and Jungner's criteria for introducing a screening programme include all of the following EXCEPT:
18. An ROC curve for two diagnostic tests (Test A and Test B) for detecting diabetes is plotted. Test A has an AUC of 0.92 and Test B has an AUC of 0.75. At the optimal cut-off, Test A shows sensitivity 88% / specificity 84%, while Test B shows 70% / 80%. Which statement is MOST accurate?
19. A screening test for colorectal cancer using faecal immunochemical test (FIT) is applied to 10,000 asymptomatic adults ≥50 years. The test has sensitivity 80% and specificity 96%. Disease prevalence is 1%. The Positive Predictive Value (PPV) of this test in this population is approximately:
20. The 'Will Rogers phenomenon' in cancer staging refers to:
21. A national cervical cancer screening programme uses VIA (visual inspection with acetic acid) rather than Pap smear as the primary screening tool in low-resource district hospitals. The primary advantage of VIA in this context is:
22. In decision analysis, which parameter represents the threshold at which a physician is indifferent between treating without testing and testing before treating?
23. A cervical cancer screening test has sensitivity 70% and specificity 80% in a population with 5% prevalence of cervical cancer. The Positive Predictive Value (PPV) of this test is approximately:
24. In evaluating a new rapid diagnostic test (RDT) for malaria, the ROC curve is plotted. A test with an AUC (Area Under the ROC Curve) of 0.95 compared to one with AUC 0.65 implies:
25. Wilson and Jungner criteria (WHO, 1968) for a valid screening programme include that the natural history of the condition should be 'adequately understood.' A disease fails this criterion most critically when:
26. Lead time bias in screening studies artificially appears to increase survival time by:
27. A community screening programme for cervical cancer using VIA (Visual Inspection with Acetic acid) is being evaluated. In a population of 10,000 women, 500 have pre-cancerous lesions (CIN 2+). VIA detects 400 of these (TP) and misses 100 (FN). Of the 9,500 without disease, 1,900 test positive (FP) and 7,600 test negative (TN). The Positive Predictive Value (PPV) of VIA in this population is:
28. A new screening test for colorectal cancer is introduced in a community. It has high sensitivity but modest specificity. The MOST important consequence of low specificity in a mass screening programme is:
29. Lead-time bias in cancer screening studies causes which of the following distortions in outcome measurement?
30. Wilson and Jungner (1968) criteria for a valid screening programme include which of the following statements as the MOST fundamental prerequisite?
31. A 45-year-old woman undergoes mammography as part of a breast cancer screening programme. The radiologist classifies the finding as BI-RADS 4B. What does this classification imply for further management?
32. A screening test has sensitivity 80% and specificity 90%. It is applied to a population with disease prevalence of 1%. Approximately, what is the Positive Predictive Value (PPV)?
33. Lead time bias in screening trials artificially increases apparent survival from time of diagnosis. The study design that best controls for lead time bias is:
34. Wilson and Jungner (1968) criteria for disease screening include multiple conditions. Which among the following is NOT one of the original Wilson-Jungner criteria?
35. In the ROC (Receiver Operating Characteristic) curve analysis of a new diagnostic test, the Area Under the Curve (AUC) is 0.92. This indicates:
36. A new rapid test for cervical cancer precursors is evaluated. In 1000 women, 50 truly have CIN-III. The test identifies 40 of these 50 (sensitivity 80%). Of the 950 who do not have CIN-III, the test incorrectly flags 95 (specificity 90%). What is the Positive Predictive Value (PPV) of this test in this population?
37. Lead time bias in cancer screening trials artificially inflates apparent survival time from diagnosis. The BEST study design to minimize lead time bias when evaluating a screening programme is:
38. Length-time bias in screening programmes means that screen-detected cancers tend to have a better prognosis because:
39. Wilson and Jungner (WHO, 1968) criteria for a screening programme state that the condition screened for must have a recognizable latent or early symptomatic stage. Which of the following conditions would FAIL this criterion for population screening?
40. The National Programme for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke (NPCDCS) recommends screening for oral, cervical, and breast cancers at PHC level. Which combination of screening tests is used for these three cancers respectively?
41. A new screening test for cervical cancer using HR-HPV DNA testing has 92% sensitivity and 88% specificity. In a population where cervical cancer prevalence is 2%, the Positive Predictive Value (PPV) is approximately:
42. A breast cancer screening programme using mammography detects cancers at a median tumour size of 10 mm, while symptomatic diagnosis occurs at 25 mm. The 5-year survival from the screened cancers is 95% vs 60% in unscreened patients. Before concluding the screening programme is effective, the evaluation must account for which bias that particularly affects survival-based evidence?
43. Wilson and Jungner criteria for initiating a population screening programme include which of the following as a MANDATORY requirement?
44. Under NCD screening in India's Ayushman Arogya Mandir (erstwhile HWC) programme, opportunistic screening for which group of conditions is mandated at the community level?
45. In a cervical cancer screening programme comparing VIA with HPV DNA testing as the primary screening tool, which statement about the two-visit versus single-visit approach is epidemiologically correct?
46. A screening test for cervical cancer using VIA (visual inspection with acetic acid) is applied to 10,000 women. Of these, 200 truly have CIN 2+ lesions, and the test correctly identifies 160 of them. The test also produces 500 false positives. What is the POSITIVE PREDICTIVE VALUE (PPV) of this test?
47. When a screening programme is designed and the cut-off value of a test is shifted to the LEFT (towards lower values) in a positively-skewed disease distribution, which of the following BEST describes the consequence?
48. The phenomenon of 'length-biased sampling' in cancer screening leads to an overestimation of screening programme benefit by preferentially detecting which type of cases?
49. In evaluation of the National Programme for Control of Blindness and Visual Impairment (NPCBVI), the National Blindness and Visual Impairment Survey India 2015–19 reported that the prevalence of blindness (visual acuity <3/60 in better eye) was approximately:
50. A screening test for diabetes has a sensitivity of 85% and specificity of 70%. In a community where the prevalence of diabetes is 5%, the Positive Predictive Value (PPV) of this test is closest to:
51. When the cut-off value for a screening test is shifted to lower levels (e.g., lowering blood glucose threshold for diabetes screening), which paired change occurs?
52. In cervical cancer screening under the National Programme for Non-Communicable Disease Control, the recommended primary screening method for resource-limited settings is:
53. A community-based screening programme for breast cancer reports improved 5-year survival compared to unscreened historical controls. A systematic reviewer cautions that this improvement may be entirely artefactual. Which TWO biases must be specifically addressed before attributing benefit to screening?
54. In Wilson and Jungner's classic criteria for a disease to be suitable for mass screening, which criterion specifically addresses the ethical dimension of early detection?
55. A screening test for cervical cancer has a sensitivity of 80% and specificity of 90% when applied to a population with a disease prevalence of 1%. What is the Positive Predictive Value (PPV) of the test?
56. Wilson and Jungner criteria for disease screening include that the condition should have a 'recognizable latent or early symptomatic stage.' Which of the following VIOLATES this criterion, making it unsuitable for mass screening?
57. A programme screens individuals at risk of diabetes annually. Over 5 years, the programme detects increasing numbers of cases, but the overall diabetes mortality does not change. Which bias MOST likely explains this apparent ineffectiveness of screening?
58. In a cancer screening programme, a pathologically slow-growing tumour is more likely to be detected than an aggressive fast-growing one. This preferential detection of clinically indolent disease is termed:
59. The 'yield' of a screening programme is MOST directly influenced by which of the following?
60. A national programme proposes cervical cancer screening by VIA (Visual Inspection with Acetic acid) every 5 years in women aged 30–65. To decide the optimal screening interval, the most critical disease characteristic is:
61. A breast cancer screening programme using mammography reports a lead time of 3 years. If a woman diagnosed by screening has 10-year survival of 80% and a woman diagnosed clinically has 7-year survival of 60%, which statement correctly interprets the 'lead time bias'?
62. The Wilson-Jungner criteria for screening list nine conditions. Which criterion is most often cited to CONTRAINDICATE population-wide screening for a disease where treatment of screen-detected cases carries a 5% serious complication rate but the disease has an annual incidence of 1 per 100,000?
63. Two-stage screening refers to a strategy where a cheap, sensitive test is followed by a specific confirmatory test in screen-positives. Which combination correctly applies this principle in the context of India's cervical cancer screening programme?
64. A screening test for cervical cancer has sensitivity 80% and specificity 90%. When applied to a population with a disease prevalence of 2%, the Positive Predictive Value (PPV) is CLOSEST to:
65. A programme manager considers reducing the cut-off value for a screening test (e.g., lowering blood glucose threshold for diabetes screening). The predictable effect on test performance is:
66. The Wilson-Jungner criteria for a good screening programme include all of the following EXCEPT:
67. Lead-time bias in cancer screening occurs when:
68. A new point-of-care rapid test for pulmonary TB is evaluated in a high-prevalence district (disease prevalence 5%). Sensitivity is 90%, specificity is 85%. The Positive Predictive Value (PPV) of this test in this setting is approximately:
69. Wilson and Jungner criteria for population-based screening include all of the following EXCEPT:
70. In the evaluation of a cervical cancer screening programme using VIA (Visual Inspection with Acetic acid), the programme shows high sensitivity but low specificity compared to Pap smear. A major consequence of low specificity in this context is:
71. A screening programme for breast cancer by mammography in a community shows a 30% reduction in breast cancer mortality among screened women compared to unscreened controls. A public health expert warns that this benefit may be overestimated due to 'lead-time bias.' Lead-time bias in screening means:
72. A new rapid test for cervical cancer screening has a sensitivity of 85% and specificity of 90% applied to a population with a prevalence of 1%. The Positive Predictive Value (PPV) is approximately:
73. When a screening programme shifts the cut-off point for a test to include more borderline cases (lowering the threshold), which of the following changes is expected?
74. A screening programme for colon cancer using colonoscopy appears to reduce cancer mortality by 35% compared to no screening in a follow-up study. However, cancers detected by screening had been present for longer before diagnosis than clinically detected cancers. This makes the screened group's survival look better even without any true benefit—this is:
75. For a population-based cancer screening programme to be worth implementing, Wilson and Jungner (1968) criteria require that the disease must satisfy which of the following conditions?
76. A new screening test for colorectal cancer is evaluated in 1,000 individuals: 100 have cancer (by gold standard). The test correctly identifies 85 cases and misses 15. Of 900 without cancer, the test is negative in 720 and positive in 180. The specificity of this test is:
77. 'Length-time bias' in cancer screening programmes refers to:
78. Wilson and Jungner's criteria for a suitable disease to screen include all of the following EXCEPT:
79. The 'number needed to screen' (NNS) to prevent one adverse outcome is mathematically:
80. Quaternary prevention, as defined by Marc Jamoulle, refers to:
81. The concept of 'primordial prevention' in cardiovascular disease was introduced by Strasser (1978) and targets:
82. A cancer screening programme reports a 40% reduction in disease-specific mortality between screened and unscreened groups. However, re-analysis accounting for 'overdiagnosis bias' reduces this to 15%. Overdiagnosis bias in cancer screening refers to:
83. Wilson and Jungner's classic criteria for a disease to be suitable for screening include all of the following EXCEPT:
84. In the Iceberg phenomenon of disease, the submerged (invisible) portion of the iceberg represents:
85. A new point-of-care test for diabetes is evaluated in 1000 subjects. Using HbA1c ≥6.5% as gold standard, 180 subjects have diabetes. The new test correctly identifies 162 of the 180 diabetics and gives positive results in 40 of the 820 non-diabetics. The Likelihood Ratio for a Positive test (LR+) is:
86. The 'Wilson and Jungner criteria' for screening include all of the following EXCEPT:
87. A screening programme for hypertension is introduced in a community. Due to earlier detection, treated individuals live longer with hypertension even though the treatment does not alter the natural history of disease. This phenomenon is called:
88. In a mass cervical cancer screening programme using VIA (Visual Inspection with Acetic acid), the test's sensitivity for CIN 2+ is 70% and specificity is 79%. Shifting the cut-off to detect more cases (increasing sensitivity to 85%) would MOST likely result in:
89. Length-time bias in cancer screening occurs because screened populations are more likely to detect:
90. Wilson and Jungner criteria for screening include that the natural history of the disease should be adequately understood. Which of the following conditions would BEST satisfy ALL major Wilson-Jungner criteria for population-based screening?
91. In screening for cervical cancer in India, which modality is recommended as the primary screening test under the National Programme for NCD Control in resource-limited settings?
92. Which of the following is NOT a prerequisite (Wilson-Jungner criterion) for a disease to be suitable for mass population screening?
93. A community screening programme detects cancer at stage I in screened individuals, who then live 8 years from diagnosis, compared to clinically diagnosed cases who live 4 years from diagnosis. However, mortality rates in the screened and unscreened populations are identical. This discrepancy is BEST explained by:
94. When a screening test's cut-off point is lowered (shifted to include more borderline positives), which of the following changes CORRECTLY describes the expected effect?
95. Length-biased sampling is a bias that affects which type of screening program, and in what direction does it distort survival estimates?
96. Wilson and Jungner (WHO, 1968) laid down criteria for a disease to be suitable for screening. Which of the following is NOT one of the Wilson-Jungner criteria?
97. A mass screening programme for hypertension in a district uses a cut-off of SBP ≥ 140 mmHg. If the programme committee decides to lower the cut-off to SBP ≥ 130 mmHg, the net effect on the screening test performance would be:
98. The ability of a screening test to correctly identify all true cases of disease in a population (not miss any cases) is best reflected by which property?
99. Wilson and Jungner criteria for disease screening include all of the following EXCEPT:
100. Levels of prevention concept was described by Leavell and Clark. Which of the following is an example of tertiary prevention?
101. When a screening test cutoff is shifted toward higher values (more stringent), the effect on test performance is:
102. Positive Predictive Value (PPV) of a screening test is MOST affected by:
103. Lead-time bias in cancer screening trials gives a false impression of improved survival because:
104. A screening test for cervical cancer has sensitivity 85% and specificity 80%. In a high-prevalence community (disease prevalence 10%), what is the Positive Predictive Value (PPV)?
105. Length-time bias in cancer screening refers to:
106. In Wilson and Jungner's (1968) criteria for mass screening, which of the following is NOT a listed criterion?
107. A new cardiac enzyme test for MI has a sensitivity of 90% and specificity of 85%. When used in an emergency department where the prevalence of MI is 40%, the Negative Predictive Value (NPV) of this test is approximately:
108. Lead-time bias in cancer screening occurs when a screened group appears to have a longer survival than an unscreened group. The most appropriate outcome measure to avoid lead-time bias when evaluating a screening programme is:
109. A screening programme for a disease detects cases earlier than they would present symptomatically. However, 5-year survival is better in screen-detected cases simply because the time of diagnosis is moved earlier, not because of any real benefit. This is called:
110. Wilson and Jungner (1968) criteria for screening require that 'The natural history of the condition, including development from latent to declared disease, should be adequately understood.' This criterion primarily ensures that:
111. In a community screen for cervical cancer, a VIA (Visual Inspection with Acetic Acid) test is used with a 'screen-and-treat' approach. VIA-positive women are immediately treated with cryotherapy in the same visit. This is described as:
112. A screening test with sensitivity 85% and specificity 90% is applied in a population with a disease prevalence of 2%. What will happen to the PPV if the test is applied in a high-risk population with a prevalence of 20%?
113. Wilson and Jungner's criteria for a good screening programme include: 'The condition should have a recognizable latent or early symptomatic stage.' This criterion is important because:
114. Lead-time bias in screening trials leads to an apparent increase in survival time. The best way to assess whether a screening programme truly reduces mortality from a disease is to measure:
115. For a screening test to be suitable, Wilson and Jungner criteria must be satisfied. Which of the following is NOT a Wilson and Jungner criterion for screening?
116. A cancer screening programme tests a population of 10,000 using a test with sensitivity 90% and specificity 95%. The disease prevalence is 1% (100 true cases). How many FALSE POSITIVES are expected?
117. Lead-time bias in cancer screening studies results in:
118. A screening programme for diabetic retinopathy is evaluated. Disease prevalence is 5%. Test sensitivity is 90%, specificity is 85%. In a population of 10,000, what is the Positive Predictive Value (PPV)?
119. Wilson and Jungner criteria for a disease to be suitable for screening include all of the following EXCEPT:
120. A mass screening programme for hypertension in a community records a sensitivity of 80% and specificity of 70%. If the programme uses two independent sequential tests (both positive required for referral), which of the following changes?
121. Wilson and Jungner criteria for ideal screening include all of the following EXCEPT:
122. A screening programme detects early-stage prostate cancer and shows a 5-year survival of 85% compared to 55% for clinically-diagnosed cases. However, mortality rates remain unchanged. This discrepancy is BEST explained by:
123. Lead time bias in cancer screening studies causes:
124. Which criterion of Bradford Hill's causation criteria is considered the MOST important single criterion for establishing causality?
125. A population-based cervical cancer screening programme uses VIA (Visual Inspection with Acetic Acid) at primary care level. The rationale for choosing VIA over Pap smear in this setting is:
126. The concept of 'iceberg phenomenon' in infectious disease epidemiology best describes:
127. A screening programme is introduced for a slow-progressing cancer with a long pre-clinical detectable phase (PCDP). Comparing screened cases with unscreened cases, survival appears longer in the screened group even though earlier diagnosis did not change the time of death. This represents:
128. For a disease with low prevalence in the general population, which characteristic of a screening test becomes MOST critical to avoid an unacceptable rate of false positives?
129. Under the AYUSHMAN BHARAT – Health and Wellness Centre (AB-HWC) programme, which additional service was added beyond the original 12 primary health services to create the comprehensive primary health care package?
130. Overdiagnosis in cancer screening refers to the detection of cancers that would never have caused symptoms or death if left undetected. This is MOST problematic in the screening of which cancer?