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Out of specification results are not rare in pharmaceutical industries but their investigation and finding the real root cause is time consuming process and includes many steps.
Out of specification is the deviation of the product from the pre-determined specification. It means when a product is unable to meet the predefined limits for that particular product.
The possible causes of the OOS can be 1. analytical error where a product doesn’t have any defect but it has a problem in its analysis and the other one is a manufacturing defect in the product where analysis is correct but the product actually has a problem.
The following are the possible causes for out of specification results.
1. Test analysis error in QC lab
2. Lab equipment malfunctioning
3. Production equipment malfunctioning
4. Operator/human errors in manufacturing
1. Test Analysis Error in QC Lab:
Error in the QC lab is human or analyst error. This is the most probable cause of the OOS and should be investigated first during the investigation of OOS. TDuring the analysis of the product, there may be an error during the handling of the sample or standard. There may be an error in sample weighing and its dilution. Errors are also possible in chromatography and titration or even in the calculation.
2. Lab Equipment Malfunctioning:
Due to this problem analysis is also unaware of the occurrence of this error. Sometimes equipment or instrument is not calibrated at the due date and it shows the incorrect results due to which product results deviate the limits. While in some other cases it happens due to malfunctioning of the equipment or instrument used in the analysis.
3. Production Equipment Malfunctioning:
This causes the actual defect in the manufactured product. Malfunctioning of equipment may include errors in timers or any other part of the equipment that is not noticed during the manufacturing process.
4. Operator/Human Errors in Manufacturing:
Operators play an important role in the manufacturing of quality products. It is happened when the operator doesn’t follow the instructions given in the batch manufacturing record. It is always very difficult to find a human error responsible for out of specification results because it may hide the errors done by him and sometimes it is done unintentionally and found correct in documents
