Screening & Prevention Flashcards
Screening, prevention, diagnostic test, gold standard, sensitivity, specificity, predictive values
Screening is what type of prevention?
Secondary prevention.
Which level of prevention aims to reduce the incidence (i.e. the number of NEW cases) of disease by controlling for specific causes and/or known risk factors of disease (typically through prevention strategies?
Primary prevention.
Which level of prevention aims to reduce the prevalence (i.e. the total number of cases) of disease or the more serious consequences of disease through early detection, diagnosis and treatment?
Secondary prevention.
Which level of prevention aims to improve the health outcome for those who already have the disease, i.e. minimise suffering and disability?
Tertiary prevention.
Which test represents the ‘truth’ because they are the best available and most accurate under reasonable conditions?
Gold Standard Tests.
What is it called when there is a correct positive result for a test, i.e. the person has the disease?
True positive.
What is it called when there is an incorrect positive result for a test, i.e. the person was incorrectly diagnosed with the disease but is actually disease-free?
False positive.
What is it called when there is a correct negative result for a test, i.e. the person does not have the disease?
True negative.
What is it called when there is an incorrect negative result for a test, i.e. the person was incorrectly diagnosed as disease-free but actually has the disease?
False negative.
Which test tells us the true positive rate?
Why?
Sensitive test.
Sensitive tests have the ability to detect people with the disease correctly. They can sometimes pick up some people with the disease who falsely test negative. In sensitive tests, we can be sure that if someone has a negative result they do not have the disease.
Remember SN N OUT.
Which test tells us the true negative rate?
Why?
Specific test.
Specific tests have the ability to determine those who do not have the disease. They can sometimes pick up people who do not have the disease but falsely test positive. In specific tests, we can be sure that if someone tests positive, they do have the disease.
Remember SP P IN.
How do you calculate the sensitivity?
SN = TP / (TP + FN)
How do you calculate the specificity?
SP = TN / (TN + FP)
Which value represents the probability that a person with the disease has a positive result in the test?
Positive predictive value.
Which value represents the probability that a person without the disease has a negative result in the test?
Negative predictive value.
