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 68-year-old man is admitted with shortness of
breath. The nurse observes a BNP result of 1,200 pg/mL
returned from the lab. The patient’s baseline is unknown and
vitals show mild tachycardia and crackles bilaterally. Which
interpretation and nursing action is best?
A. BNP of 1,200 indicates volume overload from heart failure;
notify provider and prepare for diuretic protocol.
B. BNP is nonspecific; document the result and await a repeat
test before escalation.
C. BNP at this level rules out heart failure; focus on pulmonary
causes first.
,D. BNP reflects renal function only; obtain a creatinine before
contacting the provider.
Correct answer: A
Rationale — Correct: A markedly elevated BNP supports cardiac
stretch/volume overload consistent with heart failure.
Immediate communication with the provider is appropriate
because elevated BNP with dyspnea and crackles suggests
decompensated heart failure and often warrants prompt
diuretic therapy and monitoring. Nursing priorities include
notifying the team, preparing for interventions, and continuous
respiratory/cardiac monitoring.
Rationale — Incorrect B: Waiting for a repeat delays urgent
care; BNP is clinically useful when interpreted with symptoms.
Rationale — Incorrect C: Elevated BNP supports (not rules out)
heart failure; it does not exclude cardiogenic causes.
Rationale — Incorrect D: BNP is affected by renal function but
primarily reflects cardiac wall stress; action should not be
postponed until creatinine returns.
Teaching point: Elevated BNP with dyspnea and crackles
suggests heart failure—notify provider promptly.
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 nurse orders a STAT potassium level for a patient
with muscle weakness. The lab returns potassium 6.4 mEq/L.
The specimen note says “hemolyzed.” Which interpretation and
immediate action is most appropriate?
A. Treat immediately for hyperkalemia since 6.4 mEq/L is life-
threatening.
B. Recognize hemolysis may falsely elevate potassium; request a
new non-hemolyzed specimen before treatment.
C. Ignore hemolysis; proceed to start oral potassium binder.
D. Document and recheck potassium only if ECG changes
appear.
Correct answer: B
Rationale — Correct: Hemolysis releases intracellular
potassium into serum, producing falsely elevated results. When
hemolysis is noted, confirm with a properly collected repeat
specimen before initiating potentially risky therapies, unless
patient has ECG changes or clinical instability that require
immediate treatment.
Rationale — Incorrect A: Treating solely on a hemolyzed sample
risks unnecessary therapy; clinical correlation and repeat
sampling are needed unless emergent signs exist.
Rationale — Incorrect C: Oral potassium binders are for
lowering true hyperkalemia; using them based on artifact is
inappropriate.
Rationale — Incorrect D: Waiting for ECG changes may miss
, early instability; instead obtain a repeat sample promptly and
evaluate clinical status.
Teaching point: Hemolysis can artifactually raise potassium—
confirm with a new specimen before treatment unless patient
unstable.
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 patient scheduled for a 8-hour fasting lipid panel
reports having eaten a snack two hours earlier. The lab requests
a redraw. Which rationale best explains the lab’s request and
the nurse’s correct action?
A. Post-prandial lipemia can alter triglyceride measurement;
reschedule the test after proper fasting.
B. A single snack won’t affect a lipid panel significantly; proceed
without delay.
C. Repeat testing is unnecessary because LDL is directly
measured regardless of fasting.
D. Cancel lipid testing entirely; fasting is irrelevant for
cardiovascular risk assessment.
Correct answer: A
Rationale — Correct: Triglyceride and calculated LDL values are
affected by recent food intake; an 8-hour fast is usually required
for accurate measurement. The nurse should instruct the
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TESTBANKS
Ch. 1 — Diagnostic Testing
1) Stem: A 68-year-old man is admitted with shortness of
breath. The nurse observes a BNP result of 1,200 pg/mL
returned from the lab. The patient’s baseline is unknown and
vitals show mild tachycardia and crackles bilaterally. Which
interpretation and nursing action is best?
A. BNP of 1,200 indicates volume overload from heart failure;
notify provider and prepare for diuretic protocol.
B. BNP is nonspecific; document the result and await a repeat
test before escalation.
C. BNP at this level rules out heart failure; focus on pulmonary
causes first.
,D. BNP reflects renal function only; obtain a creatinine before
contacting the provider.
Correct answer: A
Rationale — Correct: A markedly elevated BNP supports cardiac
stretch/volume overload consistent with heart failure.
Immediate communication with the provider is appropriate
because elevated BNP with dyspnea and crackles suggests
decompensated heart failure and often warrants prompt
diuretic therapy and monitoring. Nursing priorities include
notifying the team, preparing for interventions, and continuous
respiratory/cardiac monitoring.
Rationale — Incorrect B: Waiting for a repeat delays urgent
care; BNP is clinically useful when interpreted with symptoms.
Rationale — Incorrect C: Elevated BNP supports (not rules out)
heart failure; it does not exclude cardiogenic causes.
Rationale — Incorrect D: BNP is affected by renal function but
primarily reflects cardiac wall stress; action should not be
postponed until creatinine returns.
Teaching point: Elevated BNP with dyspnea and crackles
suggests heart failure—notify provider promptly.
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 nurse orders a STAT potassium level for a patient
with muscle weakness. The lab returns potassium 6.4 mEq/L.
The specimen note says “hemolyzed.” Which interpretation and
immediate action is most appropriate?
A. Treat immediately for hyperkalemia since 6.4 mEq/L is life-
threatening.
B. Recognize hemolysis may falsely elevate potassium; request a
new non-hemolyzed specimen before treatment.
C. Ignore hemolysis; proceed to start oral potassium binder.
D. Document and recheck potassium only if ECG changes
appear.
Correct answer: B
Rationale — Correct: Hemolysis releases intracellular
potassium into serum, producing falsely elevated results. When
hemolysis is noted, confirm with a properly collected repeat
specimen before initiating potentially risky therapies, unless
patient has ECG changes or clinical instability that require
immediate treatment.
Rationale — Incorrect A: Treating solely on a hemolyzed sample
risks unnecessary therapy; clinical correlation and repeat
sampling are needed unless emergent signs exist.
Rationale — Incorrect C: Oral potassium binders are for
lowering true hyperkalemia; using them based on artifact is
inappropriate.
Rationale — Incorrect D: Waiting for ECG changes may miss
, early instability; instead obtain a repeat sample promptly and
evaluate clinical status.
Teaching point: Hemolysis can artifactually raise potassium—
confirm with a new specimen before treatment unless patient
unstable.
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 patient scheduled for a 8-hour fasting lipid panel
reports having eaten a snack two hours earlier. The lab requests
a redraw. Which rationale best explains the lab’s request and
the nurse’s correct action?
A. Post-prandial lipemia can alter triglyceride measurement;
reschedule the test after proper fasting.
B. A single snack won’t affect a lipid panel significantly; proceed
without delay.
C. Repeat testing is unnecessary because LDL is directly
measured regardless of fasting.
D. Cancel lipid testing entirely; fasting is irrelevant for
cardiovascular risk assessment.
Correct answer: A
Rationale — Correct: Triglyceride and calculated LDL values are
affected by recent food intake; an 8-hour fast is usually required
for accurate measurement. The nurse should instruct the
