CLC Quality Control & Process Improvement 2

Question 1

A laboratory notices its Levey-Jennings chart shows 8 consecutive QC results on the same side of the mean. Which Westgard rule is violated?

Accepted Answer

10x rule

Answer

The 10x rule is violated when 10 consecutive QC values fall on the same side of the mean, indicating systematic bias; 8 in a row triggers the warning version of this rule.

Question 2

Which statistical tool is BEST suited for identifying the root cause of a process defect in a laboratory quality improvement project?

Accepted Answer

Fishbone (Ishikawa) diagram

Answer

A fishbone diagram systematically explores all potential causes (equipment, methods, materials, personnel, environment) contributing to a defect.

Question 3

In Six Sigma methodology, a process operating at 4-sigma has approximately what defect rate per million opportunities (DPMO)?

Accepted Answer

6,210 DPMO

Answer

A 4-sigma process produces approximately 6,210 defects per million opportunities, compared to 3.4 DPMO at the Six Sigma benchmark.

Question 4

A laboratory's reagent blank consistently reads higher than expected. Which type of error is MOST likely present?

Accepted Answer

Constant systematic error

Answer

A consistently elevated reagent blank indicates constant systematic error (additive bias) affecting all results by the same absolute amount.

Question 5

Which PDCA cycle step involves analyzing data collected during a process change to determine if the improvement was successful?

Accepted Answer

Check

Answer

The 'Check' (or Study) step of PDCA involves evaluating the collected data to assess whether the planned changes achieved the desired improvement.

(CLC) Certified Laboratory Consultant Practice Test

(CLC) Certified Laboratory Consultant Practice Test

CLC Quality Control & Process Improvement 2