FISCHBACH'S A MANUAL OF
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TESTBANKS
Ch. 1 — Diagnostic Testing
Stem: A 68-year-old man is sent to phlebotomy for routine labs
before surgery. The nurse notes the patient has been fasting
since midnight. The laboratory reports a hemolyzed serum
specimen and a markedly elevated potassium result compared
with the prior baseline. Which action should the nurse take
first?
A. Notify the surgeon of hyperkalemia and request immediate
treatment.
B. Document the hemolyzed result and schedule the operation
as planned.
C. Arrange repeat blood collection and notify the laboratory
,about hemolysis. (Correct)
D. Accept the result; hemolysis rarely alters potassium and
proceed.
Correct Answer — C
Rationale (correct): Hemolysis can artificially elevate serum
potassium by releasing intracellular potassium; repeat,
nonhemolyzed sample is needed to confirm a true
hyperkalemia before urgent treatment. The nurse must notify
the lab and repeat the draw per preanalytic error protocols.
Rationale (A): Immediate treatment is appropriate for
confirmed critical hyperkalemia with ECG changes, but this
value may be spurious due to hemolysis; confirm first.
Rationale (B): Documenting without repeat risks proceeding on
inaccurate data and endangering the patient.
Rationale (D): Hemolysis commonly affects potassium
measurements; it's not safe to accept without verification.
Teaching Point: Hemolysis frequently falsely elevates potassium
— always repeat before acting on isolated abnormal values.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2021). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
Ch. 1 — Diagnostic Testing
Stem: A 52-year-old woman is scheduled for a fasting lipid
panel. She reports she ate a small sandwich three hours before
the draw. The nurse must decide whether to proceed. Which is
the best action?
,A. Proceed; nonfasting lipids are acceptable for all clinical
decisions.
B. Proceed only if the laboratory documents nonfasting status
on the requisition.
C. Delay and reschedule the blood draw for a true fasting
specimen. (Correct)
D. Proceed and note that triglycerides will be lower after a
mixed meal.
Correct Answer — C
Rationale (correct): For tests requiring fasting (e.g., a traditional
fasting lipid panel), the nurse should reschedule to avoid
postprandial changes (especially triglycerides) that invalidate
interpretation. Proper pretest preparation must be enforced
and documented.
Rationale (A): While some guidelines accept nonfasting lipids, if
the test ordered is specifically fasting the specimen must be
fasting.
Rationale (B): Documenting nonfasting is good practice, but if
fasting is required, rescheduling is preferable to avoid
erroneous clinical decisions.
Rationale (D): A mixed meal increases triglycerides; they are
not lower postprandially, so proceeding would risk
misinterpretation.
Teaching Point: Verify and enforce pretest fasting requirements;
reschedule when fasting instructions are not met.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2021). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
, Ch. 1 — Diagnostic Testing
Stem: A nurse preparing to draw multiple tubes notices the
patient has an existing IV infusion in the right antecubital fossa.
The surgical team needs coagulation studies and a basic
metabolic panel (BMP). What is the best nursing action before
drawing?
A. Draw from the arm with the running IV without stopping
infusion.
B. Draw from the same arm but distal to the IV and document
it.
C. Stop the IV, wait 2 minutes, and draw from the same arm
proximal to the IV.
D. Draw from the opposite arm or from a site distal to the IV
after stopping infusion. (Correct)
Correct Answer — D
Rationale (correct): IV infusions can contaminate specimens
and skew results; the preferred options are using the opposite
arm or stopping the infusion and using a distal site with
appropriate discard/sample technique per preanalytic
guidelines.
Rationale (A): Drawing from an arm with an active infusion risks
sample contamination and false results.
Rationale (B): Drawing distal to an IV often yields contaminated
specimens; it’s not acceptable.
Rationale (C): Drawing proximal to the IV is unsafe and likely to
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TESTBANKS
Ch. 1 — Diagnostic Testing
Stem: A 68-year-old man is sent to phlebotomy for routine labs
before surgery. The nurse notes the patient has been fasting
since midnight. The laboratory reports a hemolyzed serum
specimen and a markedly elevated potassium result compared
with the prior baseline. Which action should the nurse take
first?
A. Notify the surgeon of hyperkalemia and request immediate
treatment.
B. Document the hemolyzed result and schedule the operation
as planned.
C. Arrange repeat blood collection and notify the laboratory
,about hemolysis. (Correct)
D. Accept the result; hemolysis rarely alters potassium and
proceed.
Correct Answer — C
Rationale (correct): Hemolysis can artificially elevate serum
potassium by releasing intracellular potassium; repeat,
nonhemolyzed sample is needed to confirm a true
hyperkalemia before urgent treatment. The nurse must notify
the lab and repeat the draw per preanalytic error protocols.
Rationale (A): Immediate treatment is appropriate for
confirmed critical hyperkalemia with ECG changes, but this
value may be spurious due to hemolysis; confirm first.
Rationale (B): Documenting without repeat risks proceeding on
inaccurate data and endangering the patient.
Rationale (D): Hemolysis commonly affects potassium
measurements; it's not safe to accept without verification.
Teaching Point: Hemolysis frequently falsely elevates potassium
— always repeat before acting on isolated abnormal values.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2021). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
Ch. 1 — Diagnostic Testing
Stem: A 52-year-old woman is scheduled for a fasting lipid
panel. She reports she ate a small sandwich three hours before
the draw. The nurse must decide whether to proceed. Which is
the best action?
,A. Proceed; nonfasting lipids are acceptable for all clinical
decisions.
B. Proceed only if the laboratory documents nonfasting status
on the requisition.
C. Delay and reschedule the blood draw for a true fasting
specimen. (Correct)
D. Proceed and note that triglycerides will be lower after a
mixed meal.
Correct Answer — C
Rationale (correct): For tests requiring fasting (e.g., a traditional
fasting lipid panel), the nurse should reschedule to avoid
postprandial changes (especially triglycerides) that invalidate
interpretation. Proper pretest preparation must be enforced
and documented.
Rationale (A): While some guidelines accept nonfasting lipids, if
the test ordered is specifically fasting the specimen must be
fasting.
Rationale (B): Documenting nonfasting is good practice, but if
fasting is required, rescheduling is preferable to avoid
erroneous clinical decisions.
Rationale (D): A mixed meal increases triglycerides; they are
not lower postprandially, so proceeding would risk
misinterpretation.
Teaching Point: Verify and enforce pretest fasting requirements;
reschedule when fasting instructions are not met.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2021). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
, Ch. 1 — Diagnostic Testing
Stem: A nurse preparing to draw multiple tubes notices the
patient has an existing IV infusion in the right antecubital fossa.
The surgical team needs coagulation studies and a basic
metabolic panel (BMP). What is the best nursing action before
drawing?
A. Draw from the arm with the running IV without stopping
infusion.
B. Draw from the same arm but distal to the IV and document
it.
C. Stop the IV, wait 2 minutes, and draw from the same arm
proximal to the IV.
D. Draw from the opposite arm or from a site distal to the IV
after stopping infusion. (Correct)
Correct Answer — D
Rationale (correct): IV infusions can contaminate specimens
and skew results; the preferred options are using the opposite
arm or stopping the infusion and using a distal site with
appropriate discard/sample technique per preanalytic
guidelines.
Rationale (A): Drawing from an arm with an active infusion risks
sample contamination and false results.
Rationale (B): Drawing distal to an IV often yields contaminated
specimens; it’s not acceptable.
Rationale (C): Drawing proximal to the IV is unsafe and likely to
