Quality Improvement, Quality Control, Quality Assurance, and Ethical/Legal/Regulatory Issues
Core concepts
Distinguish quality control (QC, the assay-level checks run with each batch: positive and negative controls, calibration, precision), quality assurance (QA, the broader program including proficiency testing, audits, and documentation), and quality improvement (QI, systematic process improvement such as PDSA cycles and root-cause analysis). Know the regulatory framework: CLIA certification, CAP accreditation, FDA oversight of laboratory-developed tests, and the role of the Clinical Laboratory Improvement Amendments in test validation.
Understand validation versus verification, analytical validity versus clinical validity versus clinical utility, and the elements of a validation study (accuracy, precision, reportable range, reference range, limit of detection, interference). Know ethical and legal concepts: informed consent, confidentiality, genetic discrimination protections (GINA), incidental findings, duty to recontact, and return of results.
Traps
Questions conflate QC with QA, or validation with verification. Another trap is assuming FDA clearance replaces laboratory validation; it does not. Be careful about the distinction between analytical sensitivity (limit of detection) and clinical sensitivity (proportion of affected patients detected).
Rule of thumb
If the question asks about a single run's controls, think QC; if it asks about the laboratory's overall system, think QA; if it asks about improving a process, think QI.
Worked example
A new NGS panel is introduced: the laboratory performs a validation study (accuracy, precision, LOD, reportable range) before clinical use, then enrolls in proficiency testing and monitors discordances as part of QA, and uses root-cause analysis when a mislabeled specimen is discovered.