Bioequivalence and Bioavailability Forum

Dear El Maestro and Constantinos,

Agreed. I would suggest you to also have a look at the EU BMV guideline, end of section 4.1.9:

Sufficient attention should be paid to the stability of the analyte in the sampled matrix directly after blood sampling of subjects and further preparation before storage, to ensure that the obtained concentrations by the analytical method reflect the concentrations of the analyte in the subject at the moment of sampling. A demonstration of this stability may be needed on a case-by-case basis, depending on the structure of the analyte.

Basically it depends on the structure of your analyte and of its metabolites, and of their known or expected stability in whole blood. Which is difficult both to predict, and to demonstrate. Meaning that keeping the tubes in an ice bath, and centrifugating them ASAP after collection, would be a useful precaution.

Regards
Ohlbe