FISCHBACH'S A MANUAL OF
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TEST BANK
1
Reference: Ch. 1 — Diagnostic Testing
Stem: A 58-year-old male is admitted with confusion and
weakness. The nurse notes that the serum potassium result
returned as 6.4 mEq/L. The specimen was hemolyzed on the lab
report. Which action should the nurse take first?
A. Administer a potassium-lowering treatment (e.g., IV insulin
with glucose) immediately.
B. Contact the laboratory to request a repeat, non-hemolyzed
specimen before acting.
C. Document the result and continue routine monitoring—
,retest only if symptoms persist.
D. Give oral potassium binder and repeat labs in the morning.
Correct Answer: B
Rationale — Correct: Hemolysis releases intracellular
potassium and can cause a spurious elevation. Before initiating
urgent therapies, the nurse should request a repeat, properly
collected specimen to confirm hyperkalemia while concurrently
assessing the patient’s clinical status. This prevents
inappropriate treatment for a false result.
Rationale — A: Treating immediately risks harm if the value is
falsely elevated; treatment is indicated if repeated result
confirms true hyperkalemia and patient shows signs.
Rationale — C: Documenting without confirmation may miss
true hyperkalemia or lead to inappropriate inaction; prompt
confirmation is required.
Rationale — D: Oral binders are not first-line emergent
treatment and waiting until morning is unsafe if the result is
real.
Teaching point: Hemolyzed specimens can falsely raise
potassium; always confirm before urgent therapy unless clinical
signs demand immediate action.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
2
,Reference: Ch. 1 — Diagnostic Testing
Stem: A patient is scheduled for a serum glucose test fasting.
The nurse inadvertently gave the patient a carbohydrate snack
30 minutes before venipuncture. Which principle should guide
the nurse’s next step?
A. Proceed with the draw and annotate the chart that the
patient was not fasting.
B. Cancel the test and reschedule for a different day; no need to
document.
C. Draw the specimen and ask the lab to correct the fasting
value using a formula.
D. Draw the specimen but do not inform the provider because a
single snack has negligible effect.
Correct Answer: A
Rationale — Correct: Pre-test preparation (fasting) is a
preanalytic variable that affects test validity. If fasting was not
observed, the nurse should proceed (if ordered urgent),
document the nonfasting status, and notify the provider
because interpretation changes. Transparent documentation
allows correct interpretation or repeat scheduling.
Rationale — B: Canceling without discussion may delay care
unnecessarily; provider may still use the result.
Rationale — C: Labs cannot reliably correct values for
noncompliance; documentation is required.
Rationale — D: A snack can significantly alter glucose;
withholding that information risks misinterpretation.
, Teaching point: Always document deviations from pre-test
instructions (e.g., fasting) and notify the provider.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
3
Reference: Ch. 1 — Diagnostic Testing
Stem: A rapid point-of-care (POC) influenza test performed in
the ED returns negative in a patient with high clinical suspicion
and symptom onset 24 hours ago. Which interpretation is most
appropriate for the nurse to communicate?
A. Negative result definitively rules out influenza; no antiviral
therapy needed.
B. Negative POC result is less reliable early in infection; consider
confirmatory PCR.
C. Treat as bacterial infection since viral tests are often false-
negative.
D. Repeat the same POC test immediately to verify the result.
Correct Answer: B
Rationale — Correct: POC antigen tests have lower sensitivity
than molecular assays, especially early or late in illness. A
negative rapid test does not definitively exclude influenza when
clinical suspicion is high; confirmatory PCR or repeat testing is
appropriate. Nurses should inform the provider about test
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TEST BANK
1
Reference: Ch. 1 — Diagnostic Testing
Stem: A 58-year-old male is admitted with confusion and
weakness. The nurse notes that the serum potassium result
returned as 6.4 mEq/L. The specimen was hemolyzed on the lab
report. Which action should the nurse take first?
A. Administer a potassium-lowering treatment (e.g., IV insulin
with glucose) immediately.
B. Contact the laboratory to request a repeat, non-hemolyzed
specimen before acting.
C. Document the result and continue routine monitoring—
,retest only if symptoms persist.
D. Give oral potassium binder and repeat labs in the morning.
Correct Answer: B
Rationale — Correct: Hemolysis releases intracellular
potassium and can cause a spurious elevation. Before initiating
urgent therapies, the nurse should request a repeat, properly
collected specimen to confirm hyperkalemia while concurrently
assessing the patient’s clinical status. This prevents
inappropriate treatment for a false result.
Rationale — A: Treating immediately risks harm if the value is
falsely elevated; treatment is indicated if repeated result
confirms true hyperkalemia and patient shows signs.
Rationale — C: Documenting without confirmation may miss
true hyperkalemia or lead to inappropriate inaction; prompt
confirmation is required.
Rationale — D: Oral binders are not first-line emergent
treatment and waiting until morning is unsafe if the result is
real.
Teaching point: Hemolyzed specimens can falsely raise
potassium; always confirm before urgent therapy unless clinical
signs demand immediate action.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
2
,Reference: Ch. 1 — Diagnostic Testing
Stem: A patient is scheduled for a serum glucose test fasting.
The nurse inadvertently gave the patient a carbohydrate snack
30 minutes before venipuncture. Which principle should guide
the nurse’s next step?
A. Proceed with the draw and annotate the chart that the
patient was not fasting.
B. Cancel the test and reschedule for a different day; no need to
document.
C. Draw the specimen and ask the lab to correct the fasting
value using a formula.
D. Draw the specimen but do not inform the provider because a
single snack has negligible effect.
Correct Answer: A
Rationale — Correct: Pre-test preparation (fasting) is a
preanalytic variable that affects test validity. If fasting was not
observed, the nurse should proceed (if ordered urgent),
document the nonfasting status, and notify the provider
because interpretation changes. Transparent documentation
allows correct interpretation or repeat scheduling.
Rationale — B: Canceling without discussion may delay care
unnecessarily; provider may still use the result.
Rationale — C: Labs cannot reliably correct values for
noncompliance; documentation is required.
Rationale — D: A snack can significantly alter glucose;
withholding that information risks misinterpretation.
, Teaching point: Always document deviations from pre-test
instructions (e.g., fasting) and notify the provider.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
3
Reference: Ch. 1 — Diagnostic Testing
Stem: A rapid point-of-care (POC) influenza test performed in
the ED returns negative in a patient with high clinical suspicion
and symptom onset 24 hours ago. Which interpretation is most
appropriate for the nurse to communicate?
A. Negative result definitively rules out influenza; no antiviral
therapy needed.
B. Negative POC result is less reliable early in infection; consider
confirmatory PCR.
C. Treat as bacterial infection since viral tests are often false-
negative.
D. Repeat the same POC test immediately to verify the result.
Correct Answer: B
Rationale — Correct: POC antigen tests have lower sensitivity
than molecular assays, especially early or late in illness. A
negative rapid test does not definitively exclude influenza when
clinical suspicion is high; confirmatory PCR or repeat testing is
appropriate. Nurses should inform the provider about test
