Help on: Out of Specification (OOS) vs Out of Trend (OOT) Results

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Question:
"I want to know how to differentiate between Out of Specification (OOS) results and Out of Trend (OOT) results?”

Answer:
“An Out of Specification (OOS) result refers to any test result that falls outside the specifications or acceptance criteria established in drug applications, drug master files (DMFs), official compendia, or by the manufacturer. The term also applies to all in-process laboratory tests that are outside of established specifications. An Out of Trend (OOT) result is a result that does not follow the expected trend, typically in a stability study. This can be either in comparison with other batches or with respect to previous results collected during a stability study. The result is not necessarily OOS but does not look like a typical data point. Both OOS and OOT results can be investigated using the same procedure.”