Quality Control

Question 1

detects errors; recognizes and minimizes Analytical Error

Answer 1

Quality control

Question 2

Quality assurance

Answer 2

prevents error

Question 3

Quality Management Systems

Answer 3

systematic actions necessary to provide confidence that lab services will satisfy medical needs for patient care

Question 4

Clinical Chemistry Training

Answer 4

• quantitative: report [analyte] (units)
• semi-quantitative: report grade of [analyte]; 0/absent, 1+, 2+…
• qualitative: report presence: (pos)/absence (neg)

Question 5

Internal QC

Answer 5

• regular statistical sampling to assess performance of lab measuring systems
• used to determine the acceptability (validity) of measurement procedure results
• known positive controls (analyte present within expected levels)
• known negative controls (analyte is not present at detectable levels)

Question 6

Batch measurement procedure

Answer 6

QC sample results must be completed before patient samples can be reported
- per each batch

Question 7

Continuous measurement procedure

Answer 7

patient samples are reported during the interval between QC measurements ; less frequent than batch

Question 8

What is ‘error’ in lab analysis?

Answer 8

• measurement is not accurate

- measurements is not reproducible

Question 9

Characteristics of Quality Control Samples (7)

Answer 9

• same matrix as the sample to be tested
• inexpensive
• ready to use
• stable for long periods
• sample directly
• assayable by independent methods
• readily available

Question 10

Establishing the control range

Answer 10

• measure analyte of interest in control sample at least 40 times under a variety of conditions
  => different days, times of day, technologists, etc.
• calculate mean, mean +/- 1sd, mean +/- 2sd, mean +/- 3sd
• Levey-Jennings Chart:
  => y-axis: mean +/- 1sd, mean +/- 2sd, mean +/- 3sd
  => x-axis: month & days of the month

Question 11

how close the measured value agrees with the ‘true’ value

Answer 11

accuracy

Question 12

reproducibility of a measured value

Answer 12

precision

Question 13

pre-analytical phase

Answer 13

test request
specimen collection
specimen transport to lab
receipt of specimens

Question 14

analytical phase

Answer 14

perform test
validate and interpret results
specimen management

Question 15

post-analytical phase

Answer 15

report results

record keeping