What is RLU?
RLU stands for Relative Light Units, which is the standard read out value given my luminometers in ATP testing. It refers to the amount of light emitted during a reaction. To interpret RLU values accurately, they must be converted to ATP concentrations using the UltraCheck Standard supplied with your kit.
Why does my RLU drop the longer I let an assay tube sit?
The ATP-luciferase interaction decreases over time as the enzyme and ATP are consumed in the reaction. The light production is stable for ~30 seconds after mixing; therefore, readings should be taken in the PhotonMaster within 5-15 seconds.
Why do I need to convert RLU to ATP concentrations?
RLUs alone are not an indicator of microbial activity - they are relative units that vary based on the activity of the enzyme. Our software automates calculating the required ATP values to harness the informational power of our test kits. It is recommended to convert RLU values to ATP concentrations before storing or making process decisions based on these values.