Chromatography Forum

Hello!

There is a long time since last time I logged in.


Now, i would be very grateful if some one could help me in the following aspect.

I work with Therapeutic drug Monitoring, in a validated method for the determination of antiretroviral agents.
Initially, the method was validated for heparinized plasma as matrix, but, now, and in order to benefit some patients whom we have plasma EDTA, and to avoid a new boold extraction; we use this plasma to quantitate.
Previously, we have passed a quintuplicate of the three levels in plasma EDTA of quality control to calculate the RSD.

Is that OK?
Have we to do another thing else?

Could someone help me?

Thank you very much

Anna

Anna,

It is a bit difficult to understand exactly what you are doing and asking..

are you asking if is ok to use calibrators and controls prepared with heparin plasma to quantitae your EDTA plasma samples? I would say this is not a good idea. You should use the same matrix as your samples.

The guidance says this type of change ("Change in anticoagulant in harvesting biological fluid") requires a partial validation.

"Partial validations are modifications of already validated bioanalytical methods. Partial validations can range from as little as one intra-assay accuracy and precision determination to a nearly full validation"

Hello

Thanks to answer.

What we did is an intra-assay accuracy and precision determination, by measuring the three quality control levels by quintuplicate.
I'm sorry if I haven't explain properly.

Thak you very much

Anna

Anna, I am always utterly confused by this sort of question about validation. Are you asking us whether you are changing volume by switching from one anticoagulation to another? We can not know that, but you should. Are you asking about other possible changes? You have to know this or find out by checking results if you can treat two portions of the same sample with the two methods. In other words, I am sort of wondering whether you (and the sundry others asking very similar questions) are after correct validation or correct analyses.
(This answer is based on the understanding that you use either heparin or EDTA, not both simultaneously).