Accuracy and precision
For within-day accuracy and precision, four concentration levels at LLOQ, LQC, MQC, and HQC in five replicates, were determined in the same day. For determination of inter-day accuracy and precision, the same concentrations were extracted and analyzed on separate days (three different days) and used for three batch runs in five replicates. The accuracy was shown as a percentage, and the acceptance criteria was that each concentration should be within ± 15% for QC samples, and within ± 20% for the LLOQ. The precision of testing was expressed as percentage of the coefficient of variation (%CV), and the acceptance criteria was that each concentration should be less than 15% for QC samples and less than 20% for LLOQ.