Laboratory Science
Understanding detection limits
What "not detected" does and does not tell you, and why limits differ between methods.
3 December 2025 · 5 min read
Detection and quantification
The limit of detection is the lowest concentration a method can reliably distinguish from zero. The limit of quantification is the lowest concentration it can reliably measure as a number.
Not detected is method-specific
A non-detect is a statement about a method's sensitivity, not proof of absence. A more sensitive method may report a value where a less sensitive one did not.
Why this matters for comparisons
Comparing results across laboratories or across time only works when detection limits and methods are comparable. Reports should always state both.