It is understandable that during an investigation the initial focus is determining the cause along with the associated impact assessment and the identification and implementation of a corrective action.  However, what can get overlooked during the investigation process is the importance of trending.  This is a key component of root cause confirmation, assessing the appropriateness and effectivity of corrective action and determining whether there are any underlying cause/s for noted repeat incidents.

For example, repeated incidents where the assigned cause is tied to analytical test method capability may indicate an underlying issue relating to the validation and/or test method transfer processes.  Similarly, repeated OOS investigations where the cause is assigned to analytical test instrumentation may suggest that there is an underlying cause linked to Analytical Instrument Qualification and/or Instrument Preventative Maintenance processes.  In both examples, the expectation from the regulatory agencies is that the trend is detected, the cause for the trend is confirmed, and that sitewide and/or company-wide corrective actions are identified and implemented along with associated impact assessments, as applicable.

In addition, it is important to trend the percentage of Laboratory OOS results that are invalidated through a confirmed laboratory error as, again, this may indicate underlying cause/s such as the laboratory training program, clarity of procedures, or lack of supervisory presence on the shop floor.

For further information or questions relating to any aspect of laboratory investigations, including trending, please contact Paul Mason, Ph.D. at or James Davison, Ph.D. at