Definition:
“Result that does not follow the expected trend, in comparison with previous results collected from past history is known as Out of Trend (ie., OOT).
There is a necessity for reliable, timely, and scientific-statistical approach to identify OOT results within reasonable time frame when a batch is not behaving as expected.
A Guide for identification of OOT results:
- A Clear Standard operating procedures (SOP) shall be defined, which shall include-selection of batches, samples, test stations, upper and lower limits.
- Although for reliable results greater batches is required, however for practical purposes, most likely around 25 to 30 batches data shall be compiled for fixing the Trend range.
- Results thus obtained from the selected 25 to 30 batches shall be tabulated, which include average mean value; minimum and maximum values are noted.
- Statistics includes: Average values, minimum, maximum, Standard deviation will be calculated for these batches. Excel spread sheet shall be used for Standard deviation calculation.
- A validated Excel sheet, if not calibrated scientific calculator shall be used.
- Maximum and minimum limits shall be taken as the Trend range for upper and lower limits by using 3 sigma method.
- Results that are obtained out of this range (that is upper and lower limits) will be considered as Out of Trend (OOT) value or Outlier value.
- Fixing Specification: However if specification of the product consist of only Not more than, then only Maximum limit for trend can be considered. Minimum limit is not included.
- Fixing Specification: However if specification has defined tolerance limit then both the Maximum and Minimum limits for trend should be considered.
5-Key Questions to be answered in establishing and execute an OOT standard operating procedures for commercial batches
A lot of difficulties that a regulated organization must overcome to execute an OOT standard operating procedures for commercial batches
- Selection of valid and reliable statistical approaches to determine OOT criterion?
- Establishing and Evaluation of OOT: Minimum data requirements? Data requirements to be used to update upper and lower limits? Is it justified?
- The execution and accountability necessities (i.e., who is accountable? What is timeframe, clear Standard operating procedures (SOP) shall be defined, and responsibility must be clearly defined?
- If OOT result is obtained as per defined SOP, further analytical testing requirements to confirm and establish the results?
- Had the OOT investigations documented into the annual product review? (updated on 20.9.2020)
After reading this blog, we hope you can understand the importance of computer system validation and properly use the proposed checklist and improve on it further.
Now that you know this:- hopefully you are in position to answer the Assignment(s)
How does one verify an OOT result? Which extra statistical analysis or analytical testing is necessary?
What role do OOT investigations play in the yearly product review?
What minimal amounts of data required for establishing OOT? If the minimal amount of data is not met, what assessment is carried out?