How do detection limit and quantification limit differ?

Why

An assay may reliably register that a biomarker is present at a low concentration but have too much variation to report the concentration accurately. Detection and quantification limits therefore support different claims. Estimate them using an approach appropriate to the method, such as signal-to-noise, calibration statistics or low-level replicate samples, and establish the decision criteria before testing.

For example, a signal clearly above a blank may be reported as detected below quantification limit rather than as 0.023 units with unsupported precision. In complex matrices, interference and lot variation can shift the limits, so evaluate them using representative samples and relevant blank materials. The exact terminology and statistical procedure should follow the domain and purpose, including ICH Q2(R2) when applicable.

Report uncertainty near the limit and do not confuse the linear range with the range in which detection alone is possible.