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Quality Control Vs Quality Assurance. How are they different?

Quality Assurance Vs Quality ControlWhat’s the difference between Quality control and Quality Assurance?

What is Quality Control?

Quality Control (QC) are the tests carried out to verify products work as expected, have no defects and are safe for consumers to use. They are the activities that, typically, take place once a product has been manufactured.  QC, through random sampling and batch testing, is a standard part of a functioning quality management system.

What is Quality Assurance?

Quality Assurance (QA) activities, on the other hand, are the actions you take to ensure a product will always be manufactured to certain specifications and quality standards.  ISO 9001 describes QA as the "part of quality management focused on providing confidence that quality requirements will be fulfilled".

Clearly QA and QC are both necessary to protect end-users of a product. Periodic QC will ensure that your Quality Assurance processes are being effective. But, as we’ve observed elsewhere you can’t “test quality into a product" by relying on QC alone.

What are the distinct features of QC vs QA?

1.Verification vs Creation

QC is about verifying the output of quality processes - QA is about creating those quality processes in the first place.

2.Product vs Process

QC is about testing ‘products’ in specified ways to make sure they’re of sufficient quality to use and distribute.

QA is about specifying the ‘way you do things’ to build ‘quality into’ a product in the first place. 

QA, therefore, seeks to define key processes and ensure they are replicated to create uniform outcomes throughout the lifecyle of a product.  

A brief look at the different processes and procedures involved in each activity should make this distinction pretty clear.

QA Processes:

  • Documentation
  • Training
  • Change control
  • Audits
  • Supplier management
  • Investigation procedures

QC Procedures:

  • Sampling
  • Batch inspection
  • Lab testing
  • Validation 


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3. Specific Personnel Vs Everyone

Typically, Quality Control activities are specific duties that are carried out in isolation by individuals or a specific business function. They are defined and finite tasks, carried out at the end (or as part of) a manufacturing process.  They are intended to capture mistakes that have already happened.

QA, on the other hand, is something that is actioned by an entire organisation throughout a production process and within their organisational culture, to prevent mistakes from happening in the first place. 

Quality Assurance is undertaken by everyone in a company:

  • Delivering/receiving training
  • Creating and updating quality documentation
  • Following SOPs
  • Contributing to the development of SOPs
  • Being involved in a process of 'continuous improvement'

4.Parts Vs Systems

QC is focused on the parts that make up the whole. For example, QCing a product that rolls off the end of a production line is just looking at a snapshot of quality in part of your organisation. Spotting an issue in that specific product might cause you to investigate and change your process, but it’s not going to correct a defect on its own.

In contrast to this, a Quality Assurance process helps you define and validate entire systems, that, working together should prevent errors being made and defects appearing in end products in the future.

5. Reactive Vs Proactive

As noted above, QC is reactive. QC activities test for quality in end products at defined moments in a process.  Results are then documented and investigative procedures are triggered to identify the source of any problems to resolve them.

QA is a much more proactive process. QA activities are, all the time, guarding against mistakes being made and potential, future quality failures - through the replication of best practice.  

Cycles of ‘continual improvement’ that are part of Quality Assurance processes require organisations to assess and reassess the way they work to improve outcomes.

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Supporting QC and QA through your eQMS

Your eQMS needs to support both your QC and QA activities, ensuring they are documented and observed in line with your internal and regulatory obligations

Quality Assurance processes can be established through:

  • the documentation of SOPs,
  • their publication on a shared digital quality management platform 
  • Used for training, auditing and continual improvement activities

At the same time, ‘quality control’ outcomes should continually feed back into your quality assurance via a CAPA process.  Your CAPA actions should trigger root cause analysis of any detected problems, and lead to optimisation of your quality processes to prevent reoccurrence of these failures.  

Your eQMS should automate and document all these processes - while making them a central part of the ‘way you do things’ and think about quality, as a business.

Both QC and QA are vital parts of a healthy and compliant Quality Management System.  Neither can exist or operate effectively without the other.  

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