BODY FLUID ANALYSIS
5TH EDITION
AUTHOR(S)NANCY A. BRUNZEL
TEST BANK
1)
Reference
Ch. 1 — Quality Assessment and Safety — Quality Control
Materials and Levey–Jennings Charts
Stem
A mid-size clinical laboratory runs daily QC for a urinary reagent
strip analyzer. Over the last 12 days, the control results plotted
,on a Levey–Jennings chart show a consistent upward drift of the
positive control mean by ~1.2 standard deviations with no
single day exceeding ±2 SD. The technologist asks whether to
take action now or continue routine monitoring. Which is the
best laboratory response?
A. Continue routine monitoring until a single QC exceeds ±2 SD.
B. Investigate potential systematic error and perform
preventative maintenance and recalibration as indicated.
C. Replace the control lot and repeat the controls; if new lot
plots similarly, accept results.
D. Report results but add an interpretive comment saying
“trend observed; correlate clinically.”
Correct answer
B
Rationale — Correct (B)
A persistent drift without breaching ±2 SD suggests a systematic
bias developing (instrument wear, reagent degradation, or
calibration shift). Investigating sources (maintenance logs,
calibration status, reagent expiration, environmental factors)
and performing corrective actions prevents future QC failures
and maintains result accuracy. Early action aligns with quality
assurance principles to detect trends before out-of-control
events.
Rationale — Incorrect
A. Waiting for ±2 SD failure ignores early trend detection and
risks reporting biased patient results.
,C. Immediately changing control lots without investigating the
instrument or procedure may mask a real systematic error.
D. Reporting without corrective action allows continued biased
results; comments don’t fix analytic issues.
Teaching point
Investigate trends early—systematic drift often precedes QC
rule violations.
Citation
Brunzel, N. A. (5th ed.). Fundamentals of Urine and Body Fluid
Analysis. Ch. 1.
2)
Reference
Ch. 1 — Quality Assessment and Safety — Westgard Rules and
QC Interpretation
Stem
Your urinalysis lab uses two levels of external QC for a
creatinine method. Today the QC results violated a 1_3s
Westgard rule (single control >3 SD). Which immediate action is
most appropriate?
A. Release patient results because only one control level failed.
B. Re-run both QC levels and review recent patient results
before any release.
C. Recalibrate the analyzer immediately, then rerun QC and
patient tests.
, D. Notify the clinician that results are delayed due to reagent
shortage.
Correct answer
B
Rationale — Correct (B)
A 1_3s violation indicates a likely random or gross error.
Standard procedure is to repeat QC to determine if failure
persists, inspect pre-analytical factors, and review recent
patient results to decide on reportability. Repeating QC
differentiates between transient errors and persistent
problems.
Rationale — Incorrect
A. Releasing results without repeat QC risks reporting
erroneous patient values.
C. Recalibration before repeat QC is premature; the failure
might be random or due to sample handling.
D. Irrelevant and avoids addressing QC failure.
Teaching point
Always repeat QC after a Westgard rule violation before
corrective actions or result release.
Citation
Brunzel, N. A. (5th ed.). Fundamentals of Urine and Body Fluid
Analysis. Ch. 1.
3)