BODY FLUID ANALYSIS
5TH EDITION
AUTHOR(S)NANCY A. BRUNZEL
TEST BANK
1.
Reference: Ch. 1 — Quality Assessment — Quality Control (QC)
Principles
Stem: A new automated urine chemistry analyzer shows a
sudden shift: daily internal QC (two levels) has trended upward
on the Levey–Jennings chart by +2 SD for the low control and +3
SD for the high control. Operator notes no maintenance
changes. Which is the best immediate laboratory action?
,A. Run patient samples; flag results pending investigation.
B. Repeat both QC levels and perform calibration verification
before releasing patient results.
C. Discard the QC data and continue testing; document the shift
in the next monthly report.
D. Replace reagents and proceed to test patient samples.
Correct Answer: B
Rationale — Correct: Repeat QC to confirm the shift, then
perform calibration verification to identify instrument drift or
calibration failure before releasing patient results. This prevents
reporting biased patient values and follows immediate QC
troubleshooting steps.
Rationale — A: Running patients before confirming QC is unsafe
and violates QC rules.
Rationale — C: Discarding data is not an acceptable corrective
action; documentation alone doesn't correct bias.
Rationale — D: Replacing reagents without verification may
miss calibration/instrument issues and is premature.
Teaching Point: Confirm QC failures with repeat runs and
calibration checks before reporting patient results.
Citation: Brunzel, N. A. (2023). Fundamentals of Urine and Body
Fluid Analysis (5th ed.). Ch. 1.
2.
,Reference: Ch. 1 — Quality Assessment — Westgard Rules &
Decision Limits
Stem: QC data for a reagent strip parameter show the following
pattern over five sequential runs: within ±2SD except one run
that is >3SD above the mean. Which Westgard rule is violated
and what is the correct interpretation?
A. 13s rule — random error likely; reject run.
B. 12s rule — warning only; continue testing.
C. 22s rule — systematic error; recalibrate.
D. R4s rule — large random error; investigate sample handling.
Correct Answer: A
Rationale — Correct: A single QC result exceeding ±3SD violates
the 13s rule, typically indicating a large random error; the run
should be rejected and repeat QC performed.
Rationale — B: 12s (±2SD) is a warning, not a single >3SD event.
Rationale — C: 22s requires two consecutive QC exceeding
same side ±2SD, indicating systematic error.
Rationale — D: R4s indicates two QC measurements in same
run differing by >4SD, suggesting random error but pattern
differs.
Teaching Point: A single >±3SD QC point (13s) signals rejectable
random error requiring repeat QC.
Citation: Brunzel, N. A. (2023). Fundamentals of Urine and Body
Fluid Analysis (5th ed.). Ch. 1.
, 3.
Reference: Ch. 1 — Quality Assessment — External Proficiency
Testing (EQA)/Proficiency Testing (PT)
Stem: Your lab receives a proficiency testing sample with a
dipstick nitrite positive and microscopic exam showing no
bacteria. PT results reported by peer labs show variable nitrite
results. What is the most appropriate lab response?
A. Report PT results as discrepant and file an incident; do not
test further.
B. Investigate reagent lot, instrument calibration, and analyst
technique; perform root cause analysis.
C. Assume peers are wrong; accept your result and certify
competency for staff.
D. Discard PT data and request a replacement sample.
Correct Answer: B
Rationale — Correct: Discrepant PT results necessitate
investigation of reagents, calibration, and technique with root
cause analysis and corrective actions to ensure accuracy. PT is a
regulatory and quality requirement.
Rationale — A: Filing an incident without investigation is
incomplete.
Rationale — C: Unwarranted confirmation bias is inappropriate;
consensus discrepancies require investigation.
Rationale — D: Requesting replacement without investigation
undermines PT integrity.