What's the Difference Between Verification and Validation?

The regulation, 21 CFR 820.75 (a) states that "where the results of a process cannot be fully verified by subsequent inspection and test, the process shall be validated...".  If we decide to verify, do we need to verify 100%?  

I get this question asked a lot during my seminars.  

The FDA hasn't provided much guidance on how we need to verify (besides using the word "fully").  I have read an article in which the authors argue that as long as we have good statistical data, we don't need 100% verification.  I started asking my students and clients.  Do you verify 100%?  And the overwhelming answer has been yes.  I found one published warning letter that deals with this issue of full verification.

does A manufacturer need to verify 100%?

In my opinion, a medical device manufacturer must either verify the output 100% or validate the process.  These are the only two choices.   Verification is done on the product coming off the production line to confirm that the line has produced a good product.  When we validate the process, we establish reliable relationships between the critical product characteristics and the process inputs.  

What are the benefits of validating?

If we do a good job during validation, we can monitor our machine inputs and should have the necessary confidence that the product is good as long as the process inputs stay in their validated operating windows.  Just finding the sweet spot of your process and then moving the process "up" and "down" to establish your process window is not good practice.  

I can't tell you how many suppliers gave me this answer when I asked them how they plan to establish their operating window.  It usually tells me that they should take some DOE training!  In order to establish long term trust in our process we need to generate objective evidence.  And lots of it!  This means that we have to establish a solid sampling plan.

should we validate even if we could verify?

We spend a significant amount of time discussing verification and validation in our seminars.   Some process outputs are easily verified, as for instance the machining of a simple aluminum bracket.  Some processes could be verified but are too expensive to do so.  

For example, a high volume metal stamping process could be verified but will most likely be more cost efficient if it the process is validated - since we do no longer have to measure every part.  Some processes need to be validated because we can't fully verify the output.  

The classical example is a bonded joint.  We can't test all the parts to failure to verify that the product meets specifications.  That is senseless.  Therefore we validate the bonding process.  And we inspect a small sample from each lot that comes off the validated process.  

processes that must be validated

What are some other processes that must be validated?  The GHTF publication (see free resources) provides a list of processes that need to be validated.  There are some processes where we need to do both, validate the process and verify the product.   As you can see, validation can make very good business sense because if your company becomes very good at validation, you will reduce cost, improve quality, drive excellence, and have a more profitable company!!!

Sign up for one of our seminars if you want to know more about verification and validation.

Medical device professionals know that risk management is a critical and integral part of Design Control.

Many engineers find the task mundane and boring and could miss some of the great benefits this tool offers. We strive to make our training practical and interesting. 

Our workshop provides a general overview of how Risk Management is integrated into a product's life cycle.  We'll discuss the different phases of risk management and how to properly link and trace risk with system requirements.  

We then look at some analysis tools.  You'll learn the difference between FMEA and FMECA, and the advantages of FTA over FMEA.  The workshop is designed to walk the student through numerous exercises.  Use our procedures for training or let us custom design the course with your procedures.  We have done so for a multi-billion dollar Med Device Firm. 

Experienced medical device engineers know how challenging it can be to meet validation criteria and to maintain validated processes!

Process validation success starts way before you write your validation plans.  Our consultants have learned first hand through trial and error how difficult it can be to pass validation requirements when specifications are unreasonable.  What should you do if you are faced with such a situation? Design engineers usually won't fudge because they passed all DV requirements.  So figure it out!   Our consultants have been on both sides of this discussion and can provide recommendations and ideas to your design and process engineers on how to increase your first pass success rate.

Injection Molding is considered a special process by the FDA.  Find out why you should validate your injection molding process.

What is a special process?  

The term special process may be used to describe a process where not all results can be fully verified after the component is made.  Verification best describes the activity of testing, measuring, or inspecting a component after it is made.  

We verify that the process made a part that meets all predetermined requirements.  We can measure all dimensions you may argue.  And you are correct.  We could verify dimensions.  

What about polymer integrity or polymer structure?  

If we mold a resin that is sensitive to moisture absorption, we need to validate the drying and molding process because we can not verify macro molecular composition of the part after it is molded.  Leave too much moisture in the part at the time of molding, and you may have a component with degraded molecules (Hydrolysis).  

The result of such degradation could be premature mechanical failure.  Or if resin is used and dried too many times, we may deplete the resin from thermal stabilizers and cause degradation once more (Thermal Degradation).  The same degradation may occur if residence time in the molding machine is too long.  

A visual inspection of a molded component will not provide any information regarding mechanical integrity.   Semi-crystalline polymers give us another reason why the molding process needs to be validated.   Cooling rate has a big impact on the part's level of crystallinity.  The percent crystallinity has a noticeable impact on mechanical behavior of the component.  

As most molders know semi-crystalline parts could deform if exposed (post-molding) to temperatures greater than the original mold temperature.  When we build medical devices we need to be sure we make parts that meet (all) specifications.  

Validating a process ensures that we mistake proof all our equipment, that we perform a thorough risk analysis, that we characterize our process, and that we demonstrate capability and repeatability.  Evaluating risk means that we understand how a change in our process affect the patient.  And that is exactly what we should do.  

Learn more about mold qualification, installation qualification of injection molding machines, risk management for injection molding, and statistics needed to demonstrate that you have a capable process.  

We teach a one day course on FDA expectations, Process Design, Installation Qualification, Operational Qualification, and Performance Qualification.  

Let us show you how to write the proper protocols, how to set up your experiments, how to analyze data, and how to present the completion report in a way that meets your customer's expectations.