Screening for Disease (Epidemiology)
Define screening
Describe the aims and objectives of the screening
Describe the differences between Screening & Diagnostic tests
List the uses of screening
Explain the types of screening, criteria for screening
Discuss the Validity of the screening test
Calculate and interpret the evaluation of the screening test
Screening is a process by which we identify the people who have the disease from those who don't have the disease by using specific tests.
It's helps in identifying the disease even before the pre symptomatic period.
It can eliminate the disease my early diagnosis or decrease the damage it causes to one person's health by early treatment .
Screening is an essential concept in the field of Medicine, specially in Preventive Medicine. This presentation covers the essentials to understand Screening of Diseases.
Screening for Disease (Epidemiology)
Define screening
Describe the aims and objectives of the screening
Describe the differences between Screening & Diagnostic tests
List the uses of screening
Explain the types of screening, criteria for screening
Discuss the Validity of the screening test
Calculate and interpret the evaluation of the screening test
Screening is a process by which we identify the people who have the disease from those who don't have the disease by using specific tests.
It's helps in identifying the disease even before the pre symptomatic period.
It can eliminate the disease my early diagnosis or decrease the damage it causes to one person's health by early treatment .
Screening is an essential concept in the field of Medicine, specially in Preventive Medicine. This presentation covers the essentials to understand Screening of Diseases.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...
chapter2-191105204556.pdf
1. Screening test and evaluation of screening test.
By Dr Nilesh Kucha
By Dr. Soujannya Kundu Chowdhury
2. DEFINITION OF SCREENING
The search for unrecognized disease or defect
applied tests, examinations or other procedures
individuals.*
by means of rapidly
in apparently healthy
The presumptive identification of unrecognized disease or defect by
the application of tests, exams or other procedures which can be
applied rapidly to sort out apparently well persons who probably have
a disease from those who probably do not.*
Tests done in individuals with no symptom or sign of an illness are
referred to as screening tests.*
21st
(* K. Park Textbook of PSM edition
; 4th
* J M Last Dictionary of Epidemiology
Papers 1968;
edition, WHO Public
Health
* J H Abramson and Z H Abramson Survey methods in Community
5th
Medicine edition)
3. BASIS OF SCREENING
Iceberg phenomenon
disease
tip of the iceberg
CLINICAL DISEASE
of
submerged portion
HIDDEN BURDEN OF DISEASE
4. BASIS OF SCREENING
Screening is a form of secondary prevention.
It detects disease in its early asymptomatic phase whereby early
treatment can be given and disease can be cured or its
progression can be delayed.
It has both diagnostic (?) and therapeutic components.
5. SCREENING TEST VERSUS DIAGNOSTIC TEST
Screening test Diagnostic test
1. Done on apparently 1. Done on sick or ill
healthy individuals
Applied to groups
individuals
Applied on single patient
Diagnosis is not final
2.
3.
2.
3.
4.
Results
final
Based
are arbitrary and
Based on evaluation of a
&
4. on one criteria no. of signs/symptoms
and cut-off lab findings
5.
6.
7.
Less
Less
Not
accurate
expensive
5.
6.
7.
More
More
Used
accurate
expensive
a basis for as a basis for
treatment
Initiative
treatment
Initiative
patient
8. comes from 8. comes from a
investigator
6. TYPES OF SCREENING
1. MASS SCREENING
Application of screening test to large, unselected population.
Everyone in the group is screened regardless of the probability of
having the disease or condition.
Example: A) mammography in women aged 40 years or less
7. 2. HIGH RISK / SELECTIVE / TARGETED SCREENING
The screening of selected high-risk groups in the population.
3. OPPORTUNISTIC / CASE FINDING
SCREENING
There is no accurate or precise diagnostic test for the disease
and where the frequency of its occurrence in the population is
small. The main objective is to detect disease and bring patients
to treatment.
8. 4. MULTIPURPOSE SCREENING
The screening of a population by more than one test done
simultaneously to detect more than one disease
5. MULTIPHASIC SCREENING
The screening in which various diagnostic procedures are
employed during the same screening program.
9. USES OF SCREENING
1. CASE DETECTION prescriptive screening, people are
screened for their own benefit
(cancer, diabetes, hypertension)
2. CONTROL OF DISEASE prospective screening, people are
screened for the benefit of others
(HIV, STI)
3. RESEARCH to know the natural history of a
disease
4. EDUCATION public awareness
10. CRITERIA FOR CHOOSING A SCREENING TEST
1. DISEASE
a) Significant burden of disease
b) Detectable and long preclinical stage of disease
c) Adequately understood natural history of disease
d) Appropriate test available for early detection of disease
e) Facilities for diagnosis of disease
f) Early detection of disease has outcome benefit
g) Effective treatment available for disease
h) Policy of screening program for disease
12. GOLD STANDARD
• GOLD STANDARD: an external source of truth regarding the
disease status of each individual in the population. Gold
standard is a benchmark
definitive.
Infections – CULTURE
and its results are considered
•
• Cancers – BIOPSY
• Drug testing – RANDOMIZED CONTROLLED TRIAL
• Cause of death – AUTOPSY
13. WHAT IS VALID AND RELIABLE?
VALIDITY IS THE ACCURACY OF A TEST.
RELIABILITY IS THE PRECISION OF A TEST.
ACCURACY: “how close is result of a test to its true value?”
PRECISION: “how close are the results of a test on repetition?”
16. SENSITIVITY
The ability of a test to correctly identify
disease.
a/ (a + c) expressed as percentage.
thosewhohavethe
Ds present Ds absent
Test positive
Test negative
17. SPECIFICITY
The ability of a test to correctly identify those
the disease.
d/ (b + d) expressed as percentage.
whodonothave
Ds present Ds absent
Test positive
Test negative
19. PROBLEM OF FN AND FP
FN: false reassurance
ignoring of disease signs and symptoms
postponement of treatment
detrimental to overall health
FP: further testing
discomfort, inconvenience,
anxiety
burden on health facilities
emotional trauma
difficulty in “de-labeling”
20. 80 of those having disease came positive and 800 of those
without disease came negative.
24. USE OF MULTIPLE TESTS
•Sequential Testing (Two-Stage Screening)
After the first (screening) test is conducted, thosewho tested
positive are brought back for the second test to further reduce
false positives.
Consequently, the overall process will increase
specificity but with reduced sensitivity.
25.
26.
27.
28.
29.
30.
31. 80 of those having disease came positive and 800 of those
without disease came negative.
Calculate positive and negative predictive value
32. PPV = 44.4%. NPV= 97.5%
Calculate positive and negative predictive value
33.
34. LIKELIHOOD RATIO
The percentage of sick people with a given test result divided by
the percentage of well individuals with the same result.
Positive LR: The relative probability of a positive test in a
diseased individual in comparison to a disease-
free individual.
TP / FP = SENSITIVITY / 1 – SPECIFICITY
35. Negative LR: The relative probability of a negative test in a
diseased individual in comparison to a disease-
free individual.
FN / TN = 1 – SENSITIVITY / SPECIFICITY
36. WHY DO WE NEED LIKELIHOOD RATIO?
• Many tests in clinical medicine have continuous results or
multiple ordinal levels. Putting multiple categories into either
positive or negative test causes loss
ratios enable clinicians to interpret
diagnostic test results.
of information. Likelihood
and use the full range of
• While predictive values relate test characteristics to
populations,
patient.
likelihood ratios can be applied to a specific
• Likelihood ratios refine clinical judgment. Application of a
likelihood ratio to a working diagnosis generally changes the
diagnostic probability—sometimes radically.
37.
38.
39.
40. EXAMPLE OF INTER-OBSERVER AND INTRA-OBSERVER
VARIATION
• INTRA-OBSERVER VARIATION:
two readings of blood pressure measurement
• INTER-OBSERVER VARIATION:
chest x-ray films by different radiologists
41. YIELD
YIELD is the amount of unrecognized disease that is detected
brought to treatment as a result of screening.
and
YIELD =TP+FP/TP+FP+TN+FN
It depends on prevalence of the disease and
screening test.
sensitivity of the
Hence, yield of a screening test is high in high – risk screening.
42. ISSUES WITH SCREENING
1. Lead time bias - the systematic error of apparent increased
survival from detecting disease in an early stage.
43.
44.
45.
46.
47.
48.
49.
50. 2. LENGTH TIME BIAS
Diseases with a long pre-clinical phase are more likely to be
detected during screening. Moreover, pre-clinical phase for the
same disease may be variable in different individuals.
51. 3. SELECTION BIAS
Not everyone will take part in a screening program. There are
factors that differ between those willing to get tested and
those who are not.
Willingness
of patient.
Example:
outcome if
outcomes if
depends on perceived risk of disease and intelligence
a) breast cancer screening – more positive
only intelligent people participate. More
negative
only high risk patients participate.
52. 4. OVERDIAGNOSIS
Screening may identify abnormalities that would never cause a
problem in a person's lifetime. Causes overestimate of disease
well as survival.
as
Example
:
a) PAP testing and Cervical CIS
b) PSA testing and low grade prostate cancer
c) mammography and DCIS
53. EVALUATIONOF SCREENING TEST
1.METHODS
a) Experimental: conduct an RCT of the screening test to
compare the disease specific cumulative
mortality rate between the intervention
and control group.
this also eliminates confounding.
allows study of distribution of lead time,
effects of early treatment and
identification of prognostic factors.
54. b) Non – experimental:
cohort
study
(comparison of advanced
disease or death rates in those
who choose to screen and those
who do not)
case - control study (comparison of
screening history in those who have
advanced disease
healthy)
and those who are
ecological study (correlation of
pattern and disease experience
populations)
screening
of several
56. BAYES THEOREM
A prior (pre-test) probability is an initial probability value originally
obtained before any additional information is obtained.
A posterior (post-test) probability is a probability value that has
been revisedby using additional information that is later obtained.
Example
:
Road traffic accident patients in a hospital are
listed and one of the patients is randomly
selected.
a) what is the probability that he will have
cerebral hemorrhage?
b) during the later analysis of this patient it was
found that he has CT scan positive for cerebral
hemorrhage. Now, what is the probability that
he actually has cerebral hemorrhage?
57. For the first question, we know that
Probability of cerebral hemorrhage in a RTA patient is 28%.
For the second question, we know that
CT scan has a sensitivity of 90% and specificity of 95% for
detecting cerebral hemorrhage.
Bayes theorem gives us a way of calculating probability of an
event in the light of presence of a second event, which itself
occurs in the presence of the first one.
58. Probability that our patient has cerebral hemorrhage, in
an already positive CT scan for cerebral hemorrhage, is…
view of
Pre-test probability of event (P1) X sensitivity of test (Sn)
--------------------------------------------------------------------------- X 100
(P1X Sn) + (1 – P1)X (1 – Sp)
Here,
P1 = 0.28
Sn = 0.90
Sp = 0.95
So,
Post-test probability (P2)= 0.875 or 87.5%