In our blog posts Lessons From the Lab we answer frequently asked questions from clients.  Find all installments of Lessons From the Lab here. 

What is a Reporting Limit?

A Reporting Limit (RL) is defined as the smallest concentration of a chemical that can be reported by a laboratory. If a laboratory is unable to detect a chemical in a sample, it does not necessarily mean that the chemical is absent from the sample altogether. It could be that the chemical concentration in the sample is below the sensitivity of the testing instrument. Concentrations below the RL are reported as not detectable at the RL or “less than” the RL. The RL value is often defined be each specific laboratory, so it is not uncommon to come across different RL’s when testing the same compound. RL’s act as safety protocols that allow laboratories to efficiently communicate the different variables correlated with testing and analyzing samples from a wide variety of sources and factors. It is important to identify the limit of concern that the client has when testing their sample to ensure that the RL is less than the regulatory limit. That enables a laboratory to identify whether a concentration of the chemical in question is above the regulatory limit of concern.