Quality Control & Process Improvement Flashcards

A forensic blood alcohol laboratory calculates a coefficient of variation (CV) of 18% for a low-level ethanol QC sample. This result MOST likely indicates:

Answer: Excessive imprecision requiring investigation

A CV of 18% at low concentrations generally exceeds acceptable precision limits (typically ≤10–15%) and warrants investigation of sources of variability.

Which process improvement methodology uses the DMAIC framework (Define, Measure, Analyze, Improve, Control)?

Answer: Six Sigma

Six Sigma employs the DMAIC framework as its structured data-driven problem-solving approach.

In a forensic laboratory, the purpose of running a method blank (reagent blank) is to:

Answer: Detect contamination introduced by reagents or sample preparation steps

A method blank undergoes the entire analytical procedure without sample, revealing any analyte contribution from reagents or the process itself.

The '5 Whys' technique in root cause analysis is BEST described as:

Answer: Iteratively asking 'why' to drill down to the fundamental cause of a problem

The 5 Whys technique repeatedly questions the cause of each answer until the root cause is identified, often requiring approximately five iterations.

A forensic laboratory's internal audit reveals that analysts are not following the documented SOP for evidence packaging. The FIRST corrective action step should be:

Answer: Determine why analysts are not following the SOP before implementing fixes

Root cause investigation must precede corrective action to ensure the fix addresses the actual reason for non-compliance rather than symptoms.

Which chart is MOST appropriate for identifying the 'vital few' causes responsible for the majority of quality defects in a forensic laboratory?

Answer: Pareto chart

A Pareto chart ranks defect categories by frequency, allowing the 80/20 principle to identify the few causes generating most defects.

In accredited forensic laboratories, proficiency testing (PT) results that fall outside acceptable performance criteria MUST be:

Answer: Investigated through root cause analysis and documented with corrective actions

Accreditation standards such as ISO/IEC 17025 require that PT failures trigger documented investigations and corrective actions to maintain accreditation status.