What is the difference between an MDL and an RL/PQL?

MDLs are the starting point within a laboratory of defining normal Reporting Limits (RLs), also called Practical Quantitation Limits (PQLs). An MDL is a value that is statistically determined and represents what can be identified above the “noise” level of an instrument as being present but not necessarily accurate. The RL/PQL is a laboratory determined value at 2 to 5 times above the MDL and can be reproduced in a manner that results in a 99% confidence level that the result is both accurate and precise.