When an analytical or test result of any batch or material is out of prescribed and predetermined limits or specifications, it is called Out of Specification. OOS may be raised in the case of stability testing, analysis of in-process, test of raw materials, intermediates, and finished goods (API). Investigation for OOS may be performed while getting any unacceptable and questionable results.
Identification of Out of Specification
Reports of Laboratory Investigation
This investigation is conducted when OOS is found in the analysis. The main purpose of obtaining OOS reports is to find out the source of the results which fall outside the specifications. In this initial investigation, all the results should be recorded and well documented. The data should be conveyed and forwarded to the quality control department to perform a full-scale analysis.
Responsibility of Analyst and Supervisor
An analyst has the primary responsibility for the laboratory testing results. He should have sound knowledge about the principle, primary requirements, and process of the investigations. The accurate and precise results are expected, if any wrong results are found they should be informed to concern superior department and assessment should be initiated with immediate effect. The supervisor of the laboratory should discuss the problems and the malfunctioned result with the analyst. He should verify the followed correct procedure and knowledge of the analyst. He should overlook the following points:
- Raw data of the result.
- Calculations of the result.
- Proper functioning of instruments.
- Procedure performed by the analyst.
- Quality parameters of solvents, reagents, standard solutions.
- Knowledge of the analyst regarding the investigation.
- Method validation and evaluation of performance.
- Preservation of the results obtained.
Identification of Out of Specification
Reports of Full-Scale Investigation
When an initial analysis does not confirm the errors caused by Out of Specification results from lab investigations, full-scale investigations with proper design should be performed. The identification of the source of the errors and the action taken for the correctness is the main objectives of this investigation. The following are the important aspects of OOS results identification for a full-scale investigation.
- Review of manufacturing, production, and sampling.
- Review of lab investigation result.
- Supplementary laboratory testing procedure.
Review of Manufacturing, Production, and Sampling
To find out the Out of Specification results, a review of manufacturing, production, and sampling is very important. The errors and problems should be investigated and identified. The documents and records of manufacturing and production should be reviewed. The investigations should be reviewed in a well-documented manner.
Review of Lab Investigation Result
It contains the following information:
- Cause of the investigation.
- Review and summary of the manufacturing process (which may have identified as malfunctioned or cause of OOS results).
- Review of previous results to find out the possible causes of OOS results.
- Review of documented records to analyze the possible factors of wrong results.
- The actions are taken to correct the process.
Supplementary Laboratory Testing Procedure
To investigate OOS results in full scale, additional laboratory testing may be performed. This includes Re-testing and Re-sampling.
In Re-testing, a portion of the original samples is tested again according to the standard procedures. The results are kept in a well-documented manner. This process helps to find out the problems encountered due to errors in instruments, process, dilution, or sample handling.
In Re-sampling, a specimen is collected from any additional units from an original sample or a new sample is prepared from the same batch and analyzed further.
Analysis of Investigated Results
The reported results should be analyzed and interpreted to find out the possible, probable, and actual causes of Out of Specification results. Some possibilities are discussed below:
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