BATES 13TH EDITION COMPREHENSIVE
EXAM 2026 STUDY GUIDE QUESTIONS AND
ANSWERS TESTED SOLUTIONS
●● Sensitivity
Answer: The probability that a person with disease has a POSITIVE test.
Also known as the "true positive" rate.
Useful for screening tests because if sensitivity is > 90%, you can rule
OUT diseases (test is rarely negative when the disease is present)
Ex) The probability that a patient with splenomegaly is associated with
percussion dullness below the left costal margin.
●● Specificity
Answer: The probability that a non-diseased person has a NEGATIVE
test.
Also known as the "true negative" rate.
Useful as confirmatory tests because if specificity is >90%, it is safe to
confirm diseases (test is rarely positive when the disease is absent)
,Ex) The probability that a patient WITHOUT splenomegaly will have
percussion dullness is the false positive rate for this physical maneuver.
●● A negative result from a test with high sensitivity...
Answer: ...usually means you can exclude the disease.
(high sensitivity = very low false-negative rate)
●● SnNOUT Acronym
Answer: a Sensitive test with a Negative result rules OUT disease
●● SpPIN Acronym
Answer: a Specific test with a Positive result rules IN disease
●● Positive Predictive Value (PPV)
Answer: The probability that a person with a positive test has disease [a /
(a + b)]
Ex) Prostate Cancer screening, where a man with a PSA value greater
than 4.0 ng/mL has only a 30% probability of having prostate cancer
when tested via biopsy.
, The predictive value will vary substantially according to the prevalence
of disease.
●● Negative Predictive Value (NPV)
Answer: The probability that a person with a negative test does not have
disease [d / (c + b)]
Ex) Among men with a PSA level of 4.0 ng/mL or below, 85% are found
to be cancer-free via biopsy.
●● Prevalence of a disease
Answer: The proportion of subjects that have the disease
●● Likelihood Ratios
Answer: 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.
This ratio tells us how much a test result changes the pre-test disease
probability (prevalence) to the post-test disease probability.
●● Likelihood ratio (LR) for a positive test
Answer: a HIGHER value (much greater than 1) indicates that a positive
test is much more likely to be coming from a diseased person than from
EXAM 2026 STUDY GUIDE QUESTIONS AND
ANSWERS TESTED SOLUTIONS
●● Sensitivity
Answer: The probability that a person with disease has a POSITIVE test.
Also known as the "true positive" rate.
Useful for screening tests because if sensitivity is > 90%, you can rule
OUT diseases (test is rarely negative when the disease is present)
Ex) The probability that a patient with splenomegaly is associated with
percussion dullness below the left costal margin.
●● Specificity
Answer: The probability that a non-diseased person has a NEGATIVE
test.
Also known as the "true negative" rate.
Useful as confirmatory tests because if specificity is >90%, it is safe to
confirm diseases (test is rarely positive when the disease is absent)
,Ex) The probability that a patient WITHOUT splenomegaly will have
percussion dullness is the false positive rate for this physical maneuver.
●● A negative result from a test with high sensitivity...
Answer: ...usually means you can exclude the disease.
(high sensitivity = very low false-negative rate)
●● SnNOUT Acronym
Answer: a Sensitive test with a Negative result rules OUT disease
●● SpPIN Acronym
Answer: a Specific test with a Positive result rules IN disease
●● Positive Predictive Value (PPV)
Answer: The probability that a person with a positive test has disease [a /
(a + b)]
Ex) Prostate Cancer screening, where a man with a PSA value greater
than 4.0 ng/mL has only a 30% probability of having prostate cancer
when tested via biopsy.
, The predictive value will vary substantially according to the prevalence
of disease.
●● Negative Predictive Value (NPV)
Answer: The probability that a person with a negative test does not have
disease [d / (c + b)]
Ex) Among men with a PSA level of 4.0 ng/mL or below, 85% are found
to be cancer-free via biopsy.
●● Prevalence of a disease
Answer: The proportion of subjects that have the disease
●● Likelihood Ratios
Answer: 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.
This ratio tells us how much a test result changes the pre-test disease
probability (prevalence) to the post-test disease probability.
●● Likelihood ratio (LR) for a positive test
Answer: a HIGHER value (much greater than 1) indicates that a positive
test is much more likely to be coming from a diseased person than from
