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?

In this post, we ask the very impor­tant ques­tion of:

Can we use some­one else’s val­i­dated method?

The short answer is “Yes, but…”

Yes, we can use some­one else’s val­i­dated method, but we must ver­ify it inde­pen­dently and with our own data in our own envi­ron­ment using our instrumentation.

If we copy some­one else’s method, we need data.

It would be as if some­one were to ask you for a blank check with reas­sur­ances of trust­ing them that they will do the right thing with your life’s earn­ings. There is an old say­ing that applies “Trust, but ver­ify.” All of us can trust, but in sci­ence we must, must ver­ify. Oth­er­wise, there is no essen­tial check on the sys­tem. This is impor­tant as import­ing some­one else’s method can be risky. What if their method was invalid?

Do you con­sent to risky surgery with­out the test results from the diag­nos­tic tests com­ing in? No one buys a house with­out a house inspec­tion, right?

Show us the data before the cru­cial and irrev­o­ca­ble deci­sion of test­ing unknowns is started.

You can­not blindly trust in science

Even if you copy some­one else’s method, your lab­o­ra­tory should have a full copy of that orig­i­nal laboratory’s doc­u­mented val­i­da­tion efforts and data. The prob­lem with foren­sic sci­ence this that there are no stan­dards such as there in in Good Lab­o­ra­tory Prac­tices (GLP) lab­o­ra­to­ries reg­u­lated by the FDA, the EPA pub­lished meth­ods, Amer­i­can Soci­ety for Test­ing and Mate­ri­als (ASTM), ISO or the USP. So, the risk of import­ing an invalid method or a non-validated method is high.

There is some guid­ance out­side of the foren­sic arena. In CITAC/EURACHEM Work­ing Group, Inter­na­tional guide to qual­ity in ana­lyt­i­cal chem­istry: An aid to accred­i­ta­tion, 2002 includes the following:

The val­i­da­tion of stan­dard or col­lab­o­ra­tively tested meth­ods should not be taken for granted, no mat­ter how impec­ca­ble the method’s pedi­gree — the lab­o­ra­tory should sat­isfy itself that the degree of val­i­da­tion of a par­tic­u­lar method is ade­quate for the required pur­pose, and that the lab­o­ra­tory is itself able to match any stated per­for­mance data.

Ver­i­fi­ca­tion is required. Can you do as they did? But more impor­tantly you must look at their val­i­da­tion data to make sure they did it right in the first place.