FISCHBACH'S A MANUAL OF
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TESTBANKS
1)
Reference
Ch. 1 — Diagnostic Testing
Stem
A 56-year-old ambulatory patient has a basic metabolic panel
returned from the lab showing an elevated serum potassium.
The patient has no ECG changes and is clinically well; a repeat
sample collected the same day without difficulty shows a
normal potassium. Which interpretation and nursing action is
most appropriate?
,A. Assume the patient has episodic hyperkalemia — place
patient on cardiac monitor and notify provider immediately.
B. Suspect a preanalytic error (hemolysis) and request the lab
comment and a redraw if needed.
C. Start potassium-lowering therapy because lab values are
authoritative over clinical assessment.
D. Document the initial result and continue routine care; no
further action is necessary.
Correct Answer
B
Rationales
Correct (B): A discrepant elevated potassium with a normal
repeat and no clinical/ECG evidence suggests
pseudohyperkalemia from preanalytic causes (eg, hemolysis,
prolonged tourniquet, difficult draw). The nurse should request
the lab indicate hemolysis and, if clinically indicated, obtain a
properly collected redraw. This links lab artifact to
pathophysiology and prioritizes appropriate action.
A: Overreacts to a likely artifact; monitoring may be reasonable
if true hyperkalemia is suspected, but immediate aggressive
action without confirming the result is not indicated.
C: Treating based solely on a possibly hemolyzed specimen risks
harm; clinical correlation and verification are required.
D: Ignoring the discrepancy fails to address potential lab error
or patient risk — the lab should be queried.
,Teaching point
Hemolysis and preanalytic errors can produce
pseudohyperkalemia; always correlate clinically and verify
abnormal results.
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 nurse prepares to collect blood cultures for a febrile patient
before starting empiric antibiotics. Which statement best
reflects proper timing and rationale?
A. Draw blood cultures after the first dose of antibiotics to
ensure specimen sterility.
B. Draw multiple sets of blood cultures before antibiotics to
maximize pathogen recovery.
C. Timing does not matter — only wound cultures need to be
collected before antibiotics.
D. Start antibiotics immediately; blood cultures are unnecessary
in immunocompetent patients.
Correct Answer
B
, Rationales
Correct (B): Blood cultures yield is highest when obtained prior
to antibiotics; multiple sets improve detection and help
distinguish contaminants. The nurse should obtain cultures
before initiating therapy when clinically feasible.
A: Antibiotics reduce culture sensitivity; drawing after dosing
can render cultures falsely negative.
C: Timing matters for many specimen types — not just wounds;
systemic infections require preantibiotic cultures.
D: With unexplained fever and suspected bacteremia, cultures
are important even in immunocompetent patients; omission
risks missing sepsis.
Teaching point
Obtain blood cultures before antibiotics when possible; multiple
sets increase diagnostic yield.
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 nurse performs a point-of-care (POC) capillary glucose on a
patient and the device displays an error and the daily quality
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TESTBANKS
1)
Reference
Ch. 1 — Diagnostic Testing
Stem
A 56-year-old ambulatory patient has a basic metabolic panel
returned from the lab showing an elevated serum potassium.
The patient has no ECG changes and is clinically well; a repeat
sample collected the same day without difficulty shows a
normal potassium. Which interpretation and nursing action is
most appropriate?
,A. Assume the patient has episodic hyperkalemia — place
patient on cardiac monitor and notify provider immediately.
B. Suspect a preanalytic error (hemolysis) and request the lab
comment and a redraw if needed.
C. Start potassium-lowering therapy because lab values are
authoritative over clinical assessment.
D. Document the initial result and continue routine care; no
further action is necessary.
Correct Answer
B
Rationales
Correct (B): A discrepant elevated potassium with a normal
repeat and no clinical/ECG evidence suggests
pseudohyperkalemia from preanalytic causes (eg, hemolysis,
prolonged tourniquet, difficult draw). The nurse should request
the lab indicate hemolysis and, if clinically indicated, obtain a
properly collected redraw. This links lab artifact to
pathophysiology and prioritizes appropriate action.
A: Overreacts to a likely artifact; monitoring may be reasonable
if true hyperkalemia is suspected, but immediate aggressive
action without confirming the result is not indicated.
C: Treating based solely on a possibly hemolyzed specimen risks
harm; clinical correlation and verification are required.
D: Ignoring the discrepancy fails to address potential lab error
or patient risk — the lab should be queried.
,Teaching point
Hemolysis and preanalytic errors can produce
pseudohyperkalemia; always correlate clinically and verify
abnormal results.
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 nurse prepares to collect blood cultures for a febrile patient
before starting empiric antibiotics. Which statement best
reflects proper timing and rationale?
A. Draw blood cultures after the first dose of antibiotics to
ensure specimen sterility.
B. Draw multiple sets of blood cultures before antibiotics to
maximize pathogen recovery.
C. Timing does not matter — only wound cultures need to be
collected before antibiotics.
D. Start antibiotics immediately; blood cultures are unnecessary
in immunocompetent patients.
Correct Answer
B
, Rationales
Correct (B): Blood cultures yield is highest when obtained prior
to antibiotics; multiple sets improve detection and help
distinguish contaminants. The nurse should obtain cultures
before initiating therapy when clinically feasible.
A: Antibiotics reduce culture sensitivity; drawing after dosing
can render cultures falsely negative.
C: Timing matters for many specimen types — not just wounds;
systemic infections require preantibiotic cultures.
D: With unexplained fever and suspected bacteremia, cultures
are important even in immunocompetent patients; omission
risks missing sepsis.
Teaching point
Obtain blood cultures before antibiotics when possible; multiple
sets increase diagnostic yield.
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 nurse performs a point-of-care (POC) capillary glucose on a
patient and the device displays an error and the daily quality
