Limit of Quantitation

Lowest quantifiable amount

The limit of quantitation (LOQ) or quantitation limit is defined in ICH Q2(R2) Validation of Analytical Procedures as, "The lowest amount of analyte in a sample which can be quantiatively determined with suitable precision and accuracy. The quantitation limit for an anlytical procedure should not be more than the reporting threshold. The quantitation limits is a parameter used for quantitaive assays for low levels of compounds in sample matrices, and particularly is used for the determination of impurites and/or degradation products." For analytical method validation measurements considered quantifiable at this level must be demonstrated with precision, accuracy and linearity under experimental conditions.