IPFC 1 Biochemistry Modules 1-3 Exam Questions and
Answers.
why do we need lab data? - Correct Answer * diagnostic and screening purposes
-discover disease, confirm suspected disorder, differentiate among different diagnosis,
detect reoccurance
* determine severity of disease
* measure efficacy and toxicity of treatment and guide course of therapy
invasive vs non-invasive lab test - Correct Answer invasive: examine fluids and tissues
obtained by needle, tube, device or scope to penetrate or enter the body. there is some
risk
non-invasive test: Test does not require skin penetration or an intrustment entering the
body. minimal risk to patients
example of invasive lab tests vs example of non-invasive lab tests - Correct Answer
invasive: blood draw from screen, lumbar puncture to take cerebral spinal fluid, tumour
biopsy
non-invasive: urine test for drug screen, BP, sweat chloride test for cystic fibrousis
accuracy vs precision - Correct Answer accuracy: extent to which the mean measure is
close to the true value
precision: agreement of results when the test is run many times on the same sample
explain what sensitivity is (in a test result interpretation). when are highly sensitive tests
desirable? - Correct Answer ability of test to identify positive results in patients who
actually have the disease. True positive rate: % of patients with the disease who actually
test positive
highly sensitive tests are desirable to test for treatable, life threatening disease, to avoid
false negatives
,SNOUT: SeNsitive test, Negative result is good for ruling OUT
what is specificity (test result interpretation)? what does it mean if test has 95%
specificity? - Correct Answer ability of test to identify negative results in patients who do
not have the disease. True negative rate: % of patients without the disease who actually
test negative.
95% specificity means there will be 95% true negative and 5% false positive rate. (5% of
people without the disease will be misidentified as having it)
SPIN: SPecific test, Positive result is good for ruling IN
formula for sensitivity vs formula for specificity - Correct Answer sensitivity: [TP/(TP+FN)]
x100%
specificity: [TN / (FP+TN)] x100%
what is sensitivity of an assay - Correct Answer the range at which an assay can
accurately measure an analyte.
ie. lower limit of detection of an immunoassay is the lowest quantity of a substance that
can be distinguished from the absence of that substance. The lower the LOD the higher
the sensitivity.
what is specificity of an assay? - Correct Answer degree of cross-reactivity of the analyze
with other substances, in other words, does the test analyze what you are looking for or is
there interference from other substances.
ie. low specificity for utine samples that test for barbiturates but could be positive in
patients who haven't even ingested barbituates but a similar structure such as phenytoin.
what does predictive value asses? what is positive vs negative predictive value? - Correct
Answer asses a test's reliability in that it considers sensitivity, specificity and prevalence of
the disease in the population.
positive predictive value: proportion of patients w positive test results who are correctly
diagnosed (who are actually positive)
, negative predictive value: percent that are actually negative
what is a type 1 error/p value? - Correct Answer false positive: test outcome is positive
when the person doesnt actually have the condition
the COVID test says positive but you dont actually have covid
what is a type II error? - Correct Answer false negative: the test is negative but you say
you have the condition.
the covid test is negative but you do have covid
a) sensitivity is percent of people with the disease and are ______ AND _______
b) when a test has high sensitivity, there is a low _____ rate
c) specificity is the percent of people WITHOUT the disease that will test negative and are
____ and _____
d) when a test has high specificity, there is a low _________ rate - Correct Answer true
positives AND false negatives
b) low false negative rate
c) true negatives and false positives
d) low false positive rate
sensitivity and specificity are inherent to ____ and not _____ - Correct Answer inherent to
the test itself an not dependent on prevalence
a) positive predicitve value represents the likelihood that _____
b) negative predictive value represents the likelihood that ________
Answers.
why do we need lab data? - Correct Answer * diagnostic and screening purposes
-discover disease, confirm suspected disorder, differentiate among different diagnosis,
detect reoccurance
* determine severity of disease
* measure efficacy and toxicity of treatment and guide course of therapy
invasive vs non-invasive lab test - Correct Answer invasive: examine fluids and tissues
obtained by needle, tube, device or scope to penetrate or enter the body. there is some
risk
non-invasive test: Test does not require skin penetration or an intrustment entering the
body. minimal risk to patients
example of invasive lab tests vs example of non-invasive lab tests - Correct Answer
invasive: blood draw from screen, lumbar puncture to take cerebral spinal fluid, tumour
biopsy
non-invasive: urine test for drug screen, BP, sweat chloride test for cystic fibrousis
accuracy vs precision - Correct Answer accuracy: extent to which the mean measure is
close to the true value
precision: agreement of results when the test is run many times on the same sample
explain what sensitivity is (in a test result interpretation). when are highly sensitive tests
desirable? - Correct Answer ability of test to identify positive results in patients who
actually have the disease. True positive rate: % of patients with the disease who actually
test positive
highly sensitive tests are desirable to test for treatable, life threatening disease, to avoid
false negatives
,SNOUT: SeNsitive test, Negative result is good for ruling OUT
what is specificity (test result interpretation)? what does it mean if test has 95%
specificity? - Correct Answer ability of test to identify negative results in patients who do
not have the disease. True negative rate: % of patients without the disease who actually
test negative.
95% specificity means there will be 95% true negative and 5% false positive rate. (5% of
people without the disease will be misidentified as having it)
SPIN: SPecific test, Positive result is good for ruling IN
formula for sensitivity vs formula for specificity - Correct Answer sensitivity: [TP/(TP+FN)]
x100%
specificity: [TN / (FP+TN)] x100%
what is sensitivity of an assay - Correct Answer the range at which an assay can
accurately measure an analyte.
ie. lower limit of detection of an immunoassay is the lowest quantity of a substance that
can be distinguished from the absence of that substance. The lower the LOD the higher
the sensitivity.
what is specificity of an assay? - Correct Answer degree of cross-reactivity of the analyze
with other substances, in other words, does the test analyze what you are looking for or is
there interference from other substances.
ie. low specificity for utine samples that test for barbiturates but could be positive in
patients who haven't even ingested barbituates but a similar structure such as phenytoin.
what does predictive value asses? what is positive vs negative predictive value? - Correct
Answer asses a test's reliability in that it considers sensitivity, specificity and prevalence of
the disease in the population.
positive predictive value: proportion of patients w positive test results who are correctly
diagnosed (who are actually positive)
, negative predictive value: percent that are actually negative
what is a type 1 error/p value? - Correct Answer false positive: test outcome is positive
when the person doesnt actually have the condition
the COVID test says positive but you dont actually have covid
what is a type II error? - Correct Answer false negative: the test is negative but you say
you have the condition.
the covid test is negative but you do have covid
a) sensitivity is percent of people with the disease and are ______ AND _______
b) when a test has high sensitivity, there is a low _____ rate
c) specificity is the percent of people WITHOUT the disease that will test negative and are
____ and _____
d) when a test has high specificity, there is a low _________ rate - Correct Answer true
positives AND false negatives
b) low false negative rate
c) true negatives and false positives
d) low false positive rate
sensitivity and specificity are inherent to ____ and not _____ - Correct Answer inherent to
the test itself an not dependent on prevalence
a) positive predicitve value represents the likelihood that _____
b) negative predictive value represents the likelihood that ________
