LOD/LOQ in RS validation
Posted: Sun Jan 25, 2009 3:16 pm
What is the significance of LOD and LOQ in related substances method validation?
Regards,
Ajay
Regards,
Ajay
Just what the names imply.
LOD (Limit of Detection) is the lowest level at which a compound can be detected (i.e., at which the peak can be reliably distinguished from the baseline noise).
LOQ (Limit of Quantitation) is the lowest level at which the amount of a compound can be reliably measured with stated accuracy and precision. Sometimes also called LLOQ (Lower Limit of Quantitation)
Measurment of small peaks is ultimately limited by the signal/noise ratio. LOD is conventionally stated as the amount of analyte that generates a peak 3x the noise. LOQ is often stated as 10x the noise. There are other (better) ways of getting at those measurements using statistics from the calibration runs, but these definitions are the easiest to understand.