In a series of posts, we are going to talk about method validation.

1. Part 1: Introduction-Is it valid, invalid or non-validated?
2. Part 2: What is method validation?
3. Part 3: Can we use some­one else’s val­i­dated method?
4. Part 4: What trig­gers ver­i­fi­ca­tion, re-validation or out right new val­i­da­tion of a method?
5. Part 5: What are the essen­tial terms in method validation?
6. Part 6: What is qual­ity assur­ance and qual­ity control?

Results of test­ing come into three basic fla­vors: Val­i­dated results, Non-validated results, and Invalid results.

These terms are very impor­tant as they will drive our under­stand­ing of our entire dis­cus­sion of method val­i­da­tion. These terms are so impor­tant that we have ded­i­cated this intro­duc­tion post to the ideas behind these terms.

Valid: Doc­u­mented proof that the ana­lyst fol­lowed a process under­taken that has been proven by test­ing and sup­ported by data to be suit­able for its intended use and achieves the intended reported result cor­rectly and uniquely. To say some­thing is valid is the high­est com­pli­ment and high­est form of approval pos­si­ble in ana­lyt­i­cal chem­istry as we can never achieve a true result. In other words, if one fol­lows the “cor­rect” process, one is pre­sumed to be “correct.”

Valid

Non-validated: If the ana­lyst devi­ates from a valid method in any way, then we have a non-validated result. It could be right, it could be wrong.

Non-validated

Invalid: Proven to be not valid. It is just wrong. Actu­ally fol­low­ing the par­tic­u­lar instruc­tions that are invalid WILL likely lead to a wrong result.

Invalid

So in just a few words: valid means “pre­sump­tively cor­rect;” non-validated means “maybe right, maybe wrong;” invalid means “proven wrong.”

How can we tell what type of result we have when we look at our testing?

How do we know what we got?

To know if the analy­sis by the ana­lyst is valid, non-validated, or invalid, one has to get the par­tic­u­lar instruc­tions (some may incor­rectly call it the Stan­dard Oper­at­ing Pro­ce­dures) of the test­ing method, but that is not enough. The most impor­tant under­ly­ing issue that is often ignored by lawyers is the fun­da­men­tal question:

Was the method ever val­i­dated to begin with?

So what if you fol­low instruc­tions per­fectly if the method is invalid? You will likely be wrong. We need to look deeper. We need to see if the method has ever been proven to be valid. These series of posts will help the lawyer exam­ine this concept.