FISCHBACH'S A MANUAL OF
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TESTBANKS
Ch. 1 — Diagnostic Testing
1) Stem: A 55-year-old woman is screened for disease X with a
test that has sensitivity 90% and specificity 95%. Her result is
positive. In a population where the disease prevalence is low
(1%), what is the most likely interpretation for this patient’s
positive result and the nurse’s immediate action?
A. The positive result most likely represents true disease;
arrange immediate treatment.
B. The positive result is more likely a false positive given low
prevalence; notify provider and recommend confirmatory
testing.
C. The test’s high sensitivity guarantees this is true disease;
schedule invasive diagnostic procedure.
,D. Prevalence doesn’t matter; treat based on positive screening
test alone.
Correct answer: B
Rationale (correct): With low disease prevalence, even tests
with high sensitivity and specificity yield low positive predictive
values; many positives are false. The nurse should notify the
provider and recommend confirmatory/diagnostic testing
before initiating definitive therapy.
Rationale (A): Incorrect — high sensitivity/specificity do not
overcome low prevalence; a positive screening test in low-
prevalence settings often is false.
Rationale (C): Incorrect — sensitivity alone doesn’t confirm
disease; invasive procedures require confirmation.
Rationale (D): Incorrect — prevalence influences predictive
values; treatment should not be based on a single screening
result.
Teaching point: Low prevalence reduces positive predictive
value; confirm positive screens.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
Ch. 1 — Diagnostic Testing
2) Stem: A rapid point-of-care (POC) influenza test has reported
sensitivity 60% and specificity 98% during peak season. A
symptomatic patient tests negative at triage. What is the best
,nursing interpretation and next step?
A. The patient does not have influenza; no further testing is
needed.
B. Because specificity is high, a negative test rules out influenza;
send the patient home.
C. Because sensitivity is modest, a negative POC test does not
reliably exclude influenza; consider confirmatory PCR if clinical
suspicion remains high.
D. The test should be repeated immediately and, if still
negative, influenza can be excluded.
Correct answer: C
Rationale (correct): Low-to-moderate sensitivity indicates false
negatives are common; when clinical suspicion is high, more
sensitive confirmatory testing (PCR) is appropriate and nursing
isolation precautions may be continued.
Rationale (A): Incorrect — a negative low-sensitivity test cannot
confidently exclude disease in symptomatic patients.
Rationale (B): Incorrect — high specificity affects false positives,
not false negatives; negative result not definitive.
Rationale (D): Incorrect — immediate repeat of same low-
sensitivity test offers limited additional information; use a more
sensitive method.
Teaching point: Low sensitivity → false negatives; confirm
negatives when clinical suspicion persists.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
, Ch. 1 — Diagnostic Testing
3) Stem: A nurse prepares a patient for a fasting lipid panel. The
patient reports they ate a meal three hours ago. Which
statement best reflects the nurse’s responsibility before
drawing blood?
A. Proceed; nonfasting lipids are equivalent and no changes
needed.
B. Document the nonfasting state and proceed because
triglycerides may be elevated; consult provider about test
timing.
C. Cancel the test and reschedule without documenting the
reason.
D. Draw the sample and mark it as fasting by default to avoid
delays.
Correct answer: B
Rationale (correct): Nonfasting meals can raise triglycerides and
alter interpretation; the nurse should document the nonfasting
state and discuss rescheduling or provider guidance.
Rationale (A): Incorrect — fasting status affects some lipid
measurements (notably triglycerides).
Rationale (C): Incorrect — cancelling without documentation or
provider notification is inappropriate.
Rationale (D): Incorrect — mislabeling fasting status is unsafe
and can lead to misinterpretation.
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TESTBANKS
Ch. 1 — Diagnostic Testing
1) Stem: A 55-year-old woman is screened for disease X with a
test that has sensitivity 90% and specificity 95%. Her result is
positive. In a population where the disease prevalence is low
(1%), what is the most likely interpretation for this patient’s
positive result and the nurse’s immediate action?
A. The positive result most likely represents true disease;
arrange immediate treatment.
B. The positive result is more likely a false positive given low
prevalence; notify provider and recommend confirmatory
testing.
C. The test’s high sensitivity guarantees this is true disease;
schedule invasive diagnostic procedure.
,D. Prevalence doesn’t matter; treat based on positive screening
test alone.
Correct answer: B
Rationale (correct): With low disease prevalence, even tests
with high sensitivity and specificity yield low positive predictive
values; many positives are false. The nurse should notify the
provider and recommend confirmatory/diagnostic testing
before initiating definitive therapy.
Rationale (A): Incorrect — high sensitivity/specificity do not
overcome low prevalence; a positive screening test in low-
prevalence settings often is false.
Rationale (C): Incorrect — sensitivity alone doesn’t confirm
disease; invasive procedures require confirmation.
Rationale (D): Incorrect — prevalence influences predictive
values; treatment should not be based on a single screening
result.
Teaching point: Low prevalence reduces positive predictive
value; confirm positive screens.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
Ch. 1 — Diagnostic Testing
2) Stem: A rapid point-of-care (POC) influenza test has reported
sensitivity 60% and specificity 98% during peak season. A
symptomatic patient tests negative at triage. What is the best
,nursing interpretation and next step?
A. The patient does not have influenza; no further testing is
needed.
B. Because specificity is high, a negative test rules out influenza;
send the patient home.
C. Because sensitivity is modest, a negative POC test does not
reliably exclude influenza; consider confirmatory PCR if clinical
suspicion remains high.
D. The test should be repeated immediately and, if still
negative, influenza can be excluded.
Correct answer: C
Rationale (correct): Low-to-moderate sensitivity indicates false
negatives are common; when clinical suspicion is high, more
sensitive confirmatory testing (PCR) is appropriate and nursing
isolation precautions may be continued.
Rationale (A): Incorrect — a negative low-sensitivity test cannot
confidently exclude disease in symptomatic patients.
Rationale (B): Incorrect — high specificity affects false positives,
not false negatives; negative result not definitive.
Rationale (D): Incorrect — immediate repeat of same low-
sensitivity test offers limited additional information; use a more
sensitive method.
Teaching point: Low sensitivity → false negatives; confirm
negatives when clinical suspicion persists.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
, Ch. 1 — Diagnostic Testing
3) Stem: A nurse prepares a patient for a fasting lipid panel. The
patient reports they ate a meal three hours ago. Which
statement best reflects the nurse’s responsibility before
drawing blood?
A. Proceed; nonfasting lipids are equivalent and no changes
needed.
B. Document the nonfasting state and proceed because
triglycerides may be elevated; consult provider about test
timing.
C. Cancel the test and reschedule without documenting the
reason.
D. Draw the sample and mark it as fasting by default to avoid
delays.
Correct answer: B
Rationale (correct): Nonfasting meals can raise triglycerides and
alter interpretation; the nurse should document the nonfasting
state and discuss rescheduling or provider guidance.
Rationale (A): Incorrect — fasting status affects some lipid
measurements (notably triglycerides).
Rationale (C): Incorrect — cancelling without documentation or
provider notification is inappropriate.
Rationale (D): Incorrect — mislabeling fasting status is unsafe
and can lead to misinterpretation.
