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 62-year-old hospitalized patient is scheduled for a
fasting metabolic panel at 0700. At 0600 the nurse documents
that the patient received a carbohydrate-containing beverage as
part of morning medication administration. The laboratory
notes “sample collected after nonfasting ingestion.” Which
action best reflects the nurse’s understanding of preanalytic
error and its clinical implications?
A. Proceed with the blood draw; the lab will adjust the
reference range to account for nonfasting status.
B. Notify the provider and reschedule the test when the patient
has completed the fasting period.
,C. Document the ingestion and proceed—fasting status rarely
changes interpretation of metabolic panels.
D. Cancel the test and order a point-of-care fingerstick instead
because it is unaffected by fasting.
Correct answer: B
Rationales
Correct Option: Rescheduling preserves test validity because
preanalytic factors (nonfasting ingestion) can alter glucose and
lipid results; nurse should notify provider and arrange
appropriate fasting collection. Preanalytic control prevents
misleading analytic results and inappropriate clinical decisions.
Incorrect Options:
A. Labs do not routinely “adjust” reference ranges for an
unplanned nonfasting state; interpretation would be
compromised.
C. Fasting status can significantly affect glucose and lipid
components—documenting alone is insufficient.
D. Point-of-care fingerstick glucose is convenient but does not
replace a properly timed fasting metabolic panel and may not
be appropriate for all ordered tests.
Teaching point: Preanalytic errors (e.g., nonfasting) require
notification and repeat collection as needed.
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 phlebotomy technician returns a hemolyzed serum
sample for a potassium level requested STAT; the lab reports
“hemolyzed—results may be falsely elevated.” The patient’s
ECG shows peaked T waves. Which nursing action is most
appropriate immediately?
A. Ignore ECG changes because hemolysis invalidates the
potassium result.
B. Treat presumptively for hyperkalemia while arranging repeat
properly collected sample.
C. Wait for a repeat serum potassium before any treatment
because treatments carry risks.
D. Document and request a venous blood gas instead, because
it’s unaffected by hemolysis.
Correct answer: B
Rationales
Correct Option: Hemolysis can falsely elevate measured
potassium, but ECG changes (peaked T waves) indicate possible
true hyperkalemia; nurse must treat emergently and obtain a
repeat sample. Clinical correlation overrides single suspect lab
value.
Incorrect Options:
A. ECG evidence of hyperkalemia is clinically significant
regardless of lab sample hemolysis and must not be ignored.
C. Waiting risks patient harm—treatment is indicated when ECG
shows hyperkalemia signs.
, D. Venous blood gas potassium is not the immediate standard
to replace a serum potassium for urgent hyperkalemia; prompt
treatment and repeat serum sample are priority.
Teaching point: Hemolyzed samples can mislead labs—treat
ECG signs of hyperkalemia immediately.
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 is collecting a capillary glucose by point-of-care
testing (POCT) in a patient who has just finished vigorous
exercise. The reading is 54 mg/dL. Which interpretation/action
aligns best with knowledge of analytic and preanalytic
influences on POCT?
A. Accept the POCT value and give the patient oral glucose
immediately.
B. Recognize recent exercise can lower capillary glucose and
confirm with a venous lab glucose before treating.
C. Ignore the POCT value because POCT devices are unreliable
after exercise.
D. Wait 30 minutes and repeat the POCT—no treatment is
indicated unless glucose falls further.
Correct answer: A
Rationales
Correct Option: A capillary glucose of 54 mg/dL is hypoglycemic
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TESTBANKS
Ch. 1 — Diagnostic Testing
Stem: A 62-year-old hospitalized patient is scheduled for a
fasting metabolic panel at 0700. At 0600 the nurse documents
that the patient received a carbohydrate-containing beverage as
part of morning medication administration. The laboratory
notes “sample collected after nonfasting ingestion.” Which
action best reflects the nurse’s understanding of preanalytic
error and its clinical implications?
A. Proceed with the blood draw; the lab will adjust the
reference range to account for nonfasting status.
B. Notify the provider and reschedule the test when the patient
has completed the fasting period.
,C. Document the ingestion and proceed—fasting status rarely
changes interpretation of metabolic panels.
D. Cancel the test and order a point-of-care fingerstick instead
because it is unaffected by fasting.
Correct answer: B
Rationales
Correct Option: Rescheduling preserves test validity because
preanalytic factors (nonfasting ingestion) can alter glucose and
lipid results; nurse should notify provider and arrange
appropriate fasting collection. Preanalytic control prevents
misleading analytic results and inappropriate clinical decisions.
Incorrect Options:
A. Labs do not routinely “adjust” reference ranges for an
unplanned nonfasting state; interpretation would be
compromised.
C. Fasting status can significantly affect glucose and lipid
components—documenting alone is insufficient.
D. Point-of-care fingerstick glucose is convenient but does not
replace a properly timed fasting metabolic panel and may not
be appropriate for all ordered tests.
Teaching point: Preanalytic errors (e.g., nonfasting) require
notification and repeat collection as needed.
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 phlebotomy technician returns a hemolyzed serum
sample for a potassium level requested STAT; the lab reports
“hemolyzed—results may be falsely elevated.” The patient’s
ECG shows peaked T waves. Which nursing action is most
appropriate immediately?
A. Ignore ECG changes because hemolysis invalidates the
potassium result.
B. Treat presumptively for hyperkalemia while arranging repeat
properly collected sample.
C. Wait for a repeat serum potassium before any treatment
because treatments carry risks.
D. Document and request a venous blood gas instead, because
it’s unaffected by hemolysis.
Correct answer: B
Rationales
Correct Option: Hemolysis can falsely elevate measured
potassium, but ECG changes (peaked T waves) indicate possible
true hyperkalemia; nurse must treat emergently and obtain a
repeat sample. Clinical correlation overrides single suspect lab
value.
Incorrect Options:
A. ECG evidence of hyperkalemia is clinically significant
regardless of lab sample hemolysis and must not be ignored.
C. Waiting risks patient harm—treatment is indicated when ECG
shows hyperkalemia signs.
, D. Venous blood gas potassium is not the immediate standard
to replace a serum potassium for urgent hyperkalemia; prompt
treatment and repeat serum sample are priority.
Teaching point: Hemolyzed samples can mislead labs—treat
ECG signs of hyperkalemia immediately.
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 is collecting a capillary glucose by point-of-care
testing (POCT) in a patient who has just finished vigorous
exercise. The reading is 54 mg/dL. Which interpretation/action
aligns best with knowledge of analytic and preanalytic
influences on POCT?
A. Accept the POCT value and give the patient oral glucose
immediately.
B. Recognize recent exercise can lower capillary glucose and
confirm with a venous lab glucose before treating.
C. Ignore the POCT value because POCT devices are unreliable
after exercise.
D. Wait 30 minutes and repeat the POCT—no treatment is
indicated unless glucose falls further.
Correct answer: A
Rationales
Correct Option: A capillary glucose of 54 mg/dL is hypoglycemic
