Dear Leng Min See,

The FDA guidance (2001) and its draft revision (edited last month) are both available on http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm064964.htm

Both documents do confirm the criteria you mentionned

Please note that these criteria are for bioanalytical methods only.

If you wish to assay a drug substance in a drug product (Quality control), these criteria would not ensure any data reliability

You may consider the attached information (in particular on p. 18)

Precision evaluation depends on the analyte and the method studied, You may obtain a guide, consulting articles in Pubmed with those key words as an entrance, If you want to obtain precision evaluation of a new method, you must run the essay with no less than 25-30 aliquots of the same sample.

Hi, CV< 15% and at lower levels CV

From my point of view, the acceptance criteria depend of the objective of your method. What is its objective (targeted concentration)? what is the considered matrix (biological or pharmaceutical)?

Hi Philippe, may I know how do you mean by the objective and the considered matrix? E.g. what would be the objective and considered matrix for ELISA test in detection of antigen? Thanks.

For instance, the objective should be the determination of an active ingredient in a tablet or the determination of the same active ingredient in the plasma (in the framework of the PK/PD study or the determination of the LLOQ in a toxicological study). Consequently, the acceptance limits for the precision are linked to the matrix but also to the objective of the study as well as the analytical method involved. These aspects should be clarified before establishing acceptance criteria for precision.

Establishing acceptance criteria for precision of a study will involve determination of LD50, protective and recovery phases and the safety of your drug