Sid Talks Testing: Fit for Purpose Testing


Fit for Purpose Lab Testing & How to get it done right, the First Time!

Every Analytical Testing Lab is different, if you haven’t already noticed.  There are many obvious ways they differ but the one thing that should not differ, theoretically speaking, is the data or the end result or at least by much.  The number that was measured by some specific technique using some specific method that uses some very expensive equipment to wonderfully provide us with the ‘right’ number. When the testing lab is given accurate, complete information from the beginning so the testing method used is fit for purpose, this process is relatively straightforward

Now, therein lies an important detail that would be worth a little time trying to understand better so that we are comfortable with the concept of the ‘right’ number or result.  The ‘right’ number, to a finished product manufacturer may mean that as long as the measured number meets the spec given by the supplier, they are happy.  However, when the ingredient supplier makes their measurement they may only be concerned that their manufacturing process consistently meets or exceeds an expected specification. Measurement accuracy is not necessarily critical to them for their intended purposes, hence the number they provide on their C of A may not agree with what a lab gets.

When this same sample is submitted for testing to an independent contract lab by a product manufacturer, to satisfy the cGMP’s, one is required to prove that the value that appears on the label reflects the actual content in the bottle. It is very important that all the right information is provided to the lab, so that an accurate measurement is performed.  As you may readily see, there are many factors that go into obtaining a meaningful number that actually satisfies the needs of all parties.  Of course, the ‘party’ that really matters is, ultimately, the FDA, or your State’s Attorney General, considering recent events.  That said, all Parties involved with the samples Chain of Custody must be able to talk the same language and be sure all understand each other so that the mutually agreed upon goal is met. That goal is the parameter being measured is accurate and meaningful and will satisfy strict analytical and regulatory scrutiny.

Now the question is, how can the Client, who is trying to stay compliant with the cGMP’s by measuring whatever it is that is on your label before it goes into the bottle, make sure this test is done correctly and accurately.  This is where a little understanding can go a long way.  In order to get your sample analyzed to produce accurate and meaningful data, there will be specific items on a Sample Submission Form (SSF) that will require special attention.  Items such as:

– the correct analyte to be measured or the correct Latin name of the botanical to be identified,

– are there any special extraction conditions that were used to prepare the test sample and what are they,

– is the substance pure or are there other substances mixed in with the substance of interest and what are they,

– is there a specification that you are trying to meet or is this a research only test, etc.?

There are many other questions, that could be answered, but if, at a minimum, these few items are addressed, this should provide the lab with the minimum information necessary to analyze the test material correctly, the first time.  On the other hand, if these questions are not all answered or are incorrectly answered, then we have multiple scenarios that could evolve.  While there are many, here are some of the more poignant ones to consider:

  1. The analytical method used is not the correct one for the analytes being tested or it is not Fit-for-Purpose.  As an example, let’s say you want total Ginsenosides measured in your finished product which is now in a different matrix than the existing method was designed for aka a blend of multiple components, possibly including some vitamins and/or other herbs.  For the uninformed, this seems like an easy task, but for the lab analyst, this is not the same as measuring the ginsenoside content in the crude raw material or the powdered extract by itself.  Even though there may be a USP or other monograph that applies to the powdered extract, once this material is combined with other components, the test method may not be Fit-for-Purpose.  The analysis is not the same now that the sample conditions have changed and there are many things to consider in order for the lab to analyze this material with any degree of accuracy.

Most people don’t realize that different sample conditions, like a crude raw material vs. a powdered extract vs. a blend, all may require different analytical testing conditions and the same method will frequently not work for each of the different matrices equally.

  1. If any of the above conditions exist, then the existing method may require additional work to prove that the method being applied to the different matrix with the same test substance in it will actually be accurate with the new or different matrix conditions.  This additional work could be as simple as adding a few relatively uncomplicated, non time consuming procedures to the existing method of analysis to insure that the ‘new’ matrix does not interfere with the measurement process.  If this type of ‘Feasibility’ study proves that the method is capable of analyzing the new matrix accurately and the testing has been determined to be ‘Scientifically Valid’ for satisfaction of the cGMP’s, then we are good to go, with a minimum of additional effort and cost.
  1. If, on the other hand, after a ‘Feasibility’ study determines there are significant issues with the ‘new’ matrix interfering with the usual method of analysis for obtaining an accurate and meaningful result, then in order for the analysis to provide an accurate result, the method will have to undergo further ‘Method Development’ and this will require further discussion between the lab and the client.

With this in mind, taking care to fill out all SSF’s accurately and with all or as much information as is available for the test that is being requested, so that the applicability of the method applied to the test material is appropriate and fit for the purpose intended, which can facilitate accuracy in testing, saving you time and money.

Sidney Sudberg

Sydney Sudberg

Each month Sidney Sudberg, Alkemist Founder & CSO, helps to demystify the science behind testing by discussing a testing-related topic.

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