Limit of blank, limit of detection and limit of quantitation.

TLDR

LoB, LoD, and LoQ define the smallest analyte concentrations that can be reliably measured, detected, or quantified by an analytical method, with LoB being the highest blank signal, LoD the lowest concentration distinguishable from LoB, and LoQ the lowest concentration meeting bias and imprecision criteria. LoB is calculated as the mean of blank replicates plus 1.645 times their standard deviation, and LoD is obtained by adding 1.645 times the standard deviation of a low‑concentration sample to the LoB. The LoQ may be equivalent to the LoD or it could be at a much higher concentration.

Abstract

* Limit of Blank (LoB), Limit of Detection (LoD), and Limit of Quantitation (LoQ) are terms used to describe the smallest concentration of a measurand that can be reliably measured by an analytical procedure. * LoB is the highest apparent analyte concentration expected to be found when replicates of a blank sample containing no analyte are tested. LoB = mean(blank) + 1.645(SD(blank)). * LoD is the lowest analyte concentration likely to be reliably distinguished from the LoB and at which detection is feasible. LoD is determined by utilising both the measured LoB and test replicates of a sample known to contain a low concentration of analyte. * LoD = LoB + 1.645(SD (low concentration sample)). * LoQ is the lowest concentration at which the analyte can not only be reliably detected but at which some predefined goals for bias and imprecision are met. The LoQ may be equivalent to the LoD or it could be at a much higher concentration.