Quality Control, QC for short, comprises operational techniques and checks used to determine whether a product, a document, a data record, or a work result fulfills predefined requirements. QC is result- and product-oriented: it detects deviations in the specific output before it is used, released, or reported.
Checking character and fields of application
QC translates quality requirements into verifiable criteria. In manufacturing, this includes sampling, testing against specifications, and evaluating test results. In clinical trials, QC can verify, for example, the completeness and consistency of a document, the plausibility of a data record, the correct programming of an analysis, or the traceability of a report. The specific design depends on risk, type of result, and defined procedure.
A QC check requires clearly defined acceptance criteria, qualified reviewers, and a documented audit trail. Errors found are not concealed but corrected according to specifications and handled traceably. Recurring or critical errors can point to a deviation or a systemic problem and trigger a root cause analysis or CAPA. QC provides important evidence for this, but is not itself the entire CAPA process.
Controls in the clinical data flow
In clinical data management, programmed checks can indicate implausible, missing, or contradictory entries. They do not replace technical evaluation when medical context or knowledge of the protocol is required. Furthermore, data transfers, coding, data cleaning listings, database locks, and tables or listings for reports can be controlled. The object of review and the scope must be determined in advance in working instructions or plans.
A data collection tool is not to be equated with QC. A CRF, electronic data capture, Interactive Response Technology, clinical outcome assessment, or a wearable can collect data. QC, however, checks whether the data record generated from them or an associated process fulfills the defined criteria. Monitoring is also not blanketly any QC: it follows its own purpose and plan for oversight of study conduct.
Distinction from Quality Assurance
Quality Assurance focuses on the quality management system and is intended to build confidence that processes are continuously suitable for fulfilling requirements. It works primarily preventively and system-oriented, for instance through audits, SOP control, and evaluating the effectiveness of quality system elements. QA asks whether a process for document reviews is appropriately designed, released, trained, and monitored.
QC applies this process to specific results. It determines through checking whether precisely this document, this batch, this data record, or this analysis fulfills the specification. QA therefore does not take over the continuous checking of every result, and QC does not replace an independent assessment of the overall system. Both complement each other in the Quality Management System: QC generates operational error insights, QA evaluates the framework and its improvement.
The scope of QC does not have to be identical in every case. ICH Q9 requires adapting effort, formality, and level of documentation to the quality risk. High importance for participant protection, product quality, or the reliability of a study conclusion can therefore require a more intensive or independent check. A risk-based selection needs traceable criteria; it must not lead to an unjustified reduction in necessary controls.
In the documentation, the object of review, version used, criteria, review result, detected errors, corrections, and release status should be apparent. For electronic systems, access rights, audit trail, and controlled changes are essential prerequisites for a retrospective reconstruction. With this, QC not only delivers a result, but evidence of how the quality of this result was assessed.
The design of QC should already be considered when planning a process. If requirements are unclear, versions not controlled, or criteria not measurable, a subsequent control cannot generate a reliable release. Checking steps must therefore match the type of result and its intended use. A more critical check can require, for example, an independent secondary review or an in-depth evaluation of outliers. Conversely, a well-reasoned, standardized control can be appropriate for recurring results. It is decisive that the scope is not chosen out of habit, but documented, qualified, and re-evaluated in the event of changes or trends.
For each QC checking step, the review protocol and release documents record the object of review, version used, specification limits, results, and corrections. In the event of an out-of-specification result, the investigation must show how the finding was evaluated and on what basis the batch or data record was released or rejected.
Relevance for clinical trials
Quality control supports reliable study results when it addresses quality-critical data and documents. Typical risks lie in inconsistent data transfers, incomplete releases, incorrect reports, or unclear correction pathways. ICH E6(R3) requires appropriate QA and QC processes as well as systems that can correctly collect, manage, and analyze data.
Full-service CROs such as Mediconomics provide support through QC plans for data management and medical writing, independent document reviews, controlled database locks, and tracking of detected errors. They coordinate these controls with monitoring, biostatistics, pharmacovigilance, and quality management so that quality-critical results are reviewed and traceably released before further use.
Frequently Asked Questions (FAQ)
Is QC only a laboratory topic?
No. QC can relate to any defined result, such as batches, documents, clinical data, programming, or reports.
Does an automatic check replace quality control?
Automated checks can be a QC tool. However, their suitability, configuration, and the technical evaluation of hits must be regulated.
Are causes of errors determined with QC?
QC detects and documents errors in the result. A systematic root cause analysis and action planning take place as needed within the deviation or CAPA process.
Regulatory references
- EudraLex Volume 4, Part I, Chapter 6 “Quality Control” – contains GMP requirements for quality control.
- ICH Q9 Quality Risk Management – requires risk-proportionate scope and level of documentation of quality measures.
- ICH E6(R3) Good Clinical Practice – requires appropriate QA and QC processes in clinical trials.