Wk 1 - Clin Reas, Pt Hx, Cul Humil, SOAP Flashcards
Probability of Diagnosis
Determines testing and treatment
Probability of diagnosis includes thresholds ___ and area between them represents _____.
Testing threshold
Treatment threshold
Area between them represents “clinical uncertainty”.
Test results will enable you to cross a threshold.
Testing and Treatment Thresholds are not static and are impacted by:
Thresholds are impacted by risk and benefit of treatment and seriousness of condition.
Initial step in evaluating a diagnostic test
Determine VALIDITY of results
2x2 Table is the basic format for ___
evaluating performance of a diagnostic test.
2x2 Table helps determine how much the _____ will revise _______
2x2 table determines how much test results will revise the probability of a disease.
Sensitivity is:
The probability that a person with disease has a positive test
Sensitivity is also known as
…the true positive rate.
Specificity is:
…the probability that a non-diseased person has a negative test
Specificity is also known as
…the true negative rate.
Sensitivity is represented by the equation…
a/(a + c) in the disease present column of the 2 × 2 table.
Specificity is represented by the equation…
d/(b + d) in the disease absent column of the 2 × 2 table
Highly SENSITIVE test has a very high/low….
high sensitivity: very low false-negative rate
Highly SPECIFIC test has a very high/low…
high specificity: very low false-positive rate
A SENSITIVE test with a NEGATIVE result…
A SENSITIVE test with a NEGATIVE result RULES OUT disease.
A SPECIFIC test with a POSITIVE result…
A SPECIFIC test with a POSITIVE result RULES IN disease.
SnNOUT means:
A SENSITIVE test with a NEGATIVE result RULES OUT disease.
SpPIN
A SPECIFIC test with a POSITIVE result RULES IN disease.
The positive predictive value (PPV) is:
The positive predictive value (PPV) is the probability that a person with a positive test HAS disease, represented as a/(a + b) from the test positive row in the 2 × 2 table.
The negative predictive value (NPV) is:
The negative predictive value (NPV) is the probability that a person with a negative test does NOT have disease, represented as d/(c + d) in the test negative row in the 2 × 2 table.
Positive predictive value and negative predictive value are impacted by the variable…
Positive predictive value and negative predictive value are impacted by the prevalence of disease in the population
Likelihood ratio is the…
Likelihood ratio is the probability of obtaining a given test result in a diseased patient divided by the probability of obtaining a given test result in a non-diseased patient.
Likelihood ratio: A lower value…
Likelihood ratio: A lower value (much <1) indicates that the negative test is much more likely to be coming from a non-diseased person than from a diseased person, increasing our confidence that a person with a negative result does not have disease.
Likelihood ratio: A higher value…
Likelihood ratio: A higher value (much >1) indicates that a positive test is much more likely to be coming from a diseased person than from a non-diseased person, increasing our confidence that a person with a positive result has disease.
The likelihood ratio for a positive test is the ratio:
The likelihood ratio for a positive test is the ratio of the probability of getting a positive test result in a diseased person divided by the probability of getting a positive test result in a non-diseased person. HIGHER value increases confidence that the person with a positive result has disease.
The likelihood ratio for a negative test is the ratio:
The likelihood ratio for a negative test is the ratio of the probability of getting a negative test result in a diseased person divided by the probability of getting a a negative test result in a non-diseased person. LOWER value increases confidence that a person with a negative result does not have the disease.
