FISCHBACH'S A MANUAL OF
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TEST BANK
1)
Ch. 1 — Diagnostic Testing
A 68-year-old man with sudden onset weakness has a point-of-
care (bedside) capillary glucose of 42 mg/dL. The nurse repeats
the fingerstick on the opposite hand and obtains 138 mg/dL.
Which interpretation and immediate nursing action is most
appropriate?
A. Accept the second result; treat conservatively for mild
hypoglycemia.
B. Treat for hypoglycemia immediately while arranging a venous
glucose confirmatory test.
,C. Discard both results because capillary testing is unreliable
and wait for lab serum glucose.
D. Notify the provider but take no action until a third capillary
test is obtained.
Correct answer: B
Rationale — Correct: A symptomatic patient with one low POC
glucose and a subsequent higher reading may still be
hypoglycemic; the nurse should treat promptly for
hypoglycemia while obtaining a confirmatory venous glucose
because delay risks harm. Immediate treatment is a priority in
POC critical-value situations.
Rationale — A (incorrect): Accepting the second reading risks
delaying treatment if the first low value was accurate;
conservative treatment alone is insufficient without
confirmatory testing being arranged.
Rationale — C (incorrect): Capillary POCT is useful and often
reliable; discarding both without action endangers the patient.
Rationale — D (incorrect): Waiting for a third test without
treating the potential hypoglycemia unnecessarily delays care.
Teaching point: Treat suspected hypoglycemia promptly;
confirmatory lab testing can follow stabilizing treatment.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
2)
,Ch. 1 — Diagnostic Testing
A nurse prepares to draw a vancomycin trough for a patient.
The provider orders the trough at 09:00; however, the patient’s
last dose was at 06:30. Which action best follows preanalytic
timing principles?
A. Draw the trough at 09:00 as ordered (2.5 hours post-dose).
B. Request the trough be delayed until immediately before the
next scheduled dose.
C. Draw the trough immediately and label it “random” so the
lab can adjust interpretation.
D. Draw the trough at 08:00 to standardize to a 12-hour dosing
interval.
Correct answer: B
Rationale — Correct: Trough levels should be drawn
immediately before the next scheduled dose to reflect the
lowest concentration; delaying or rescheduling the order is
appropriate.
Rationale — A (incorrect): Drawing 2.5 hours after dose will not
represent a trough and may lead to misinterpretation and
incorrect dosing adjustments.
Rationale — C (incorrect): While labeling is helpful, a random
level is not equivalent to a trough and will not guide dosing
properly.
Rationale — D (incorrect): Arbitrarily drawing at 08:00 without
relation to dosing schedule risks an invalid trough.
, Teaching point: Trough samples must be drawn immediately
before the next dose for valid interpretation.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
3)
Ch. 1 — Diagnostic Testing
A blood sample for potassium returns 6.3 mEq/L. The nurse
notes the sample was difficult to obtain with multiple redrawn
attempts and visible hemolysis in the tube. What is the most
appropriate interpretation and action?
A. Treat the patient for hyperkalemia immediately — this value
is critical.
B. Recognize possible pseudohyperkalemia from hemolysis;
repeat a clean venous draw.
C. Ignore hemolysis; report the result as accurate because lab
machines detect hemolysis.
D. Draw an arterial sample instead because venous draws give
false potassium values.
Correct answer: B
Rationale — Correct: Hemolysis artificially releases intracellular
potassium, causing pseudohyperkalemia. Repeat with a
properly collected venous sample before treating if the patient
is asymptomatic.
Rationale — A (incorrect): Immediate treatment is required if
LABORATORY AND DIAGNOSTIC TESTS.
11TH EDITION
• AUTHOR(S)FRANCES FISCHBACH;
MARGARET FISCHBACH; KATE STOUT
TEST BANK
1)
Ch. 1 — Diagnostic Testing
A 68-year-old man with sudden onset weakness has a point-of-
care (bedside) capillary glucose of 42 mg/dL. The nurse repeats
the fingerstick on the opposite hand and obtains 138 mg/dL.
Which interpretation and immediate nursing action is most
appropriate?
A. Accept the second result; treat conservatively for mild
hypoglycemia.
B. Treat for hypoglycemia immediately while arranging a venous
glucose confirmatory test.
,C. Discard both results because capillary testing is unreliable
and wait for lab serum glucose.
D. Notify the provider but take no action until a third capillary
test is obtained.
Correct answer: B
Rationale — Correct: A symptomatic patient with one low POC
glucose and a subsequent higher reading may still be
hypoglycemic; the nurse should treat promptly for
hypoglycemia while obtaining a confirmatory venous glucose
because delay risks harm. Immediate treatment is a priority in
POC critical-value situations.
Rationale — A (incorrect): Accepting the second reading risks
delaying treatment if the first low value was accurate;
conservative treatment alone is insufficient without
confirmatory testing being arranged.
Rationale — C (incorrect): Capillary POCT is useful and often
reliable; discarding both without action endangers the patient.
Rationale — D (incorrect): Waiting for a third test without
treating the potential hypoglycemia unnecessarily delays care.
Teaching point: Treat suspected hypoglycemia promptly;
confirmatory lab testing can follow stabilizing treatment.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
2)
,Ch. 1 — Diagnostic Testing
A nurse prepares to draw a vancomycin trough for a patient.
The provider orders the trough at 09:00; however, the patient’s
last dose was at 06:30. Which action best follows preanalytic
timing principles?
A. Draw the trough at 09:00 as ordered (2.5 hours post-dose).
B. Request the trough be delayed until immediately before the
next scheduled dose.
C. Draw the trough immediately and label it “random” so the
lab can adjust interpretation.
D. Draw the trough at 08:00 to standardize to a 12-hour dosing
interval.
Correct answer: B
Rationale — Correct: Trough levels should be drawn
immediately before the next scheduled dose to reflect the
lowest concentration; delaying or rescheduling the order is
appropriate.
Rationale — A (incorrect): Drawing 2.5 hours after dose will not
represent a trough and may lead to misinterpretation and
incorrect dosing adjustments.
Rationale — C (incorrect): While labeling is helpful, a random
level is not equivalent to a trough and will not guide dosing
properly.
Rationale — D (incorrect): Arbitrarily drawing at 08:00 without
relation to dosing schedule risks an invalid trough.
, Teaching point: Trough samples must be drawn immediately
before the next dose for valid interpretation.
Citation: Fischbach, F., Fischbach, M., & Stout, K. (2024). A
Manual of Laboratory and Diagnostic Tests (11th ed.). Ch. 1.
3)
Ch. 1 — Diagnostic Testing
A blood sample for potassium returns 6.3 mEq/L. The nurse
notes the sample was difficult to obtain with multiple redrawn
attempts and visible hemolysis in the tube. What is the most
appropriate interpretation and action?
A. Treat the patient for hyperkalemia immediately — this value
is critical.
B. Recognize possible pseudohyperkalemia from hemolysis;
repeat a clean venous draw.
C. Ignore hemolysis; report the result as accurate because lab
machines detect hemolysis.
D. Draw an arterial sample instead because venous draws give
false potassium values.
Correct answer: B
Rationale — Correct: Hemolysis artificially releases intracellular
potassium, causing pseudohyperkalemia. Repeat with a
properly collected venous sample before treating if the patient
is asymptomatic.
Rationale — A (incorrect): Immediate treatment is required if
