FUNDAMENTALS OF URINE AND
BODY FLUID ANALYSIS
5TH EDITION
AUTHOR(S)NANCY A. BRUNZEL
TEST BANK
1
Reference
Ch. 1 — Quality Assessment and Safety — Quality indicators
and performance monitoring
Stem (MLS-level)
A urine chemistry analyzer shows a small but consistent positive
bias for specific gravity compared with manual refractometer
readings over the past 10 days. Internal QC values are within
limits, but the mean of patient-specific gravity values has
,shifted upward. Which action best evaluates whether this
represents a clinically significant bias versus acceptable
variation?
Options
A. Continue routine testing because internal QC is within limits.
B. Run an external proficiency sample (PT) with known specific
gravity to compare results.
C. Recalibrate the analyzer immediately and discard previous
patient results.
D. Reduce the analyzer’s QC frequency and monitor patient
means for another week.
Correct Answer
B
Rationales
Correct (B): Running an external proficiency or reference
sample provides an independent assessment of method
accuracy and distinguishes true bias from internal QC
variability; it tests method trueness against an external target.
A: Internal QC within limits does not exclude systematic bias —
QC monitors precision more than trueness.
C: Immediate recalibration without verification could mask
intermittent causes (e.g., lot-to-lot reagent shift) and discards
potentially valid data; verification should precede corrective
action.
D: Reducing QC frequency risks missing real shifts and is poor
quality practice.
,Teaching Point
Use external reference material to confirm suspected analyzer
bias before corrective action.
Citation
Brunzel, N. A. (2023). Fundamentals of Urine and Body Fluid
Analysis (5th ed.). Ch. 1.
2
Reference
Ch. 1 — Quality Assessment and Safety — Westgard rules and
control interpretation
Stem (MLS-level)
A urinalysis lab uses Levey–Jennings charts with Westgard rules.
On run 1, controls show 1: 1s violation (one control exceeds +2
SD). On run 2, same control shows 2: 2s (two consecutive
results exceed +2 SD). Which interpretation and next step are
most appropriate?
Options
A. Accept the run; 1s and 2s are warning only, no action
needed.
B. Reject the run and perform instrument maintenance
immediately.
C. Investigate for systematic error (reagent lot, calibrator,
instrument), rerun controls and patient samples after corrective
action.
, D. Discard the control that failed and continue testing with
remaining controls.
Correct Answer
C
Rationales
Correct (C): 2:2s indicates a systematic error; protocol requires
investigation of potential causes (calibration, reagent lot,
instrument drift), corrective action, and rerunning controls and
affected patient samples.
A: 1:1s is a warning but progression to 2:2s demands action —
acceptance without investigation is unsafe.
B: Maintenance may be appropriate but should be based on
identified cause; blanket maintenance without investigation is
inefficient.
D: Discarding controls invalidates QC integrity and hides
problems; not acceptable.
Teaching Point
Progression of Westgard rule violations signals systematic error
— investigate, correct, and verify before reporting results.
Citation
Brunzel, N. A. (2023). Fundamentals of Urine and Body Fluid
Analysis (5th ed.). Ch. 1.
3
BODY FLUID ANALYSIS
5TH EDITION
AUTHOR(S)NANCY A. BRUNZEL
TEST BANK
1
Reference
Ch. 1 — Quality Assessment and Safety — Quality indicators
and performance monitoring
Stem (MLS-level)
A urine chemistry analyzer shows a small but consistent positive
bias for specific gravity compared with manual refractometer
readings over the past 10 days. Internal QC values are within
limits, but the mean of patient-specific gravity values has
,shifted upward. Which action best evaluates whether this
represents a clinically significant bias versus acceptable
variation?
Options
A. Continue routine testing because internal QC is within limits.
B. Run an external proficiency sample (PT) with known specific
gravity to compare results.
C. Recalibrate the analyzer immediately and discard previous
patient results.
D. Reduce the analyzer’s QC frequency and monitor patient
means for another week.
Correct Answer
B
Rationales
Correct (B): Running an external proficiency or reference
sample provides an independent assessment of method
accuracy and distinguishes true bias from internal QC
variability; it tests method trueness against an external target.
A: Internal QC within limits does not exclude systematic bias —
QC monitors precision more than trueness.
C: Immediate recalibration without verification could mask
intermittent causes (e.g., lot-to-lot reagent shift) and discards
potentially valid data; verification should precede corrective
action.
D: Reducing QC frequency risks missing real shifts and is poor
quality practice.
,Teaching Point
Use external reference material to confirm suspected analyzer
bias before corrective action.
Citation
Brunzel, N. A. (2023). Fundamentals of Urine and Body Fluid
Analysis (5th ed.). Ch. 1.
2
Reference
Ch. 1 — Quality Assessment and Safety — Westgard rules and
control interpretation
Stem (MLS-level)
A urinalysis lab uses Levey–Jennings charts with Westgard rules.
On run 1, controls show 1: 1s violation (one control exceeds +2
SD). On run 2, same control shows 2: 2s (two consecutive
results exceed +2 SD). Which interpretation and next step are
most appropriate?
Options
A. Accept the run; 1s and 2s are warning only, no action
needed.
B. Reject the run and perform instrument maintenance
immediately.
C. Investigate for systematic error (reagent lot, calibrator,
instrument), rerun controls and patient samples after corrective
action.
, D. Discard the control that failed and continue testing with
remaining controls.
Correct Answer
C
Rationales
Correct (C): 2:2s indicates a systematic error; protocol requires
investigation of potential causes (calibration, reagent lot,
instrument drift), corrective action, and rerunning controls and
affected patient samples.
A: 1:1s is a warning but progression to 2:2s demands action —
acceptance without investigation is unsafe.
B: Maintenance may be appropriate but should be based on
identified cause; blanket maintenance without investigation is
inefficient.
D: Discarding controls invalidates QC integrity and hides
problems; not acceptable.
Teaching Point
Progression of Westgard rule violations signals systematic error
— investigate, correct, and verify before reporting results.
Citation
Brunzel, N. A. (2023). Fundamentals of Urine and Body Fluid
Analysis (5th ed.). Ch. 1.
3
