In a regulatory GLP environment the archiving retention time is sometimes defined in national legislation. However, where there is no retention time specified, the OECD recommends that records and materials should be retained for as long as receiving authorities might request GLP audits of the respective studies and at least three inspection cycles so that inspectors can evaluate the GLP compliance of the test facility and the respective studies (OECD, 2007[8]).
Retention arrangements must be designed to protect data, records and materials from deliberate or accidental changes, manipulations or deletions thus ensuring integrity throughout the retention period. Archiving is defined as the long-term retention of completed data and relevant metadata, records or materials. Archived data, records or materials may need to be stored for many years and must be permanently locked so that no changes can be made without detection. In the case of paper records, archive design and conditions must protect contents from untimely deterioration. In addition to this, they should be easily retrieved for regulatory inspections.
The archives must be designed so as to allow for the archiving of documents and records and also for the archiving of study samples and materials (e.g., slides, specimens, test items and reference material) under suitable storage conditions (OECD, 2007[8]). The OECD Principles of GLP state that: "a sample for analytical purposes from each batch of test item should be retained for all studies except short-term studies". The same rules apply to these archives as apply to the paper based archive, i.e., access restrictions, retrieval and removal of items, etc.
The storage conditions should be optimal for these samples and often these archives will require dedicated storage facilities, e.g., low temperature storage such as -20oC, liquid nitrogen storage or storage of items under inert conditions. Where special storage equipment is required, the rules governing the control and maintenance of this equipment must be applied. Where computerised systems are used, these systems must also follow the facility's policy regarding the use of computerised systems, including qualification and validation of such systems (OECD, 2016[5]).
Samples of test and reference items or specimens may however be discarded when the quality of the material no longer permits evaluation. Obviously, the storage conditions should be optimal for these samples. It is also good practice to refer to the storage devices’ history to determine equipment failures, power outages, moves, that could possibly impact sample integrity. When samples of test and reference items or specimens are disposed of before the end of the required retention period, the reason for disposal should be justified and documented (e.g., the reason might be perishable specimens such as blood smears, freeze-dried preparations and wet tissues).
Data is generated during the experimental phase of studies and during this phase the integrity of the data must be ensured until final archiving of the study. This data will usually be required for further analysis and as such will not be formally archived until the completion of the study. It is important that access to this data, both electronic and hard copies, is controlled until the final archiving upon completion of the study. It is recommended, where possible or feasible, that the electronic data is set as read-only or that an audit trail is provided, detailing who did what and when.
The GLP Principles for archiving must be applied consistently to electronic and non-electronic data. It is therefore important that electronic data is stored with the same levels of access control, indexing and expedient "retrieval" as non-electronic data. Electronic archiving should be regarded as an independent procedure which should be validated appropriately. A risk assessment should be applied when designing and validating the archiving procedure. Relevant hosting systems and data formats should be evaluated regarding accessibility, readability and influences on data integrity during the archiving period.
When electronic archiving is performed, the archiving system, both hardware and software, must be designated as a computerised system and validated as such so as to ensure the integrity of data stored electronically over its life-time. If the data storage media, the data formats, the hardware or software of the archiving system changes during the archiving period, the system should be revalidated so as to ensure that there is no negative influence on the accessibility, readability and integrity of the archived data and that the ability to retrieve the data has not been compromised. Where problems with long-term access to data are envisaged or when computerised systems have to be retired, procedures for ensuring continued readability of the data should be established. This may, for example, include producing hard copy printouts or converting data to a different format or transferring data to another system. If migration of data including conversion to a different data format or printing is relevant, the requirements of this guidance for data migration should be met. Risk assessment, change control, configuration management and testing regime should be considered as relevant standard procedures when changes in the archiving system are required. As content and integrity of any electronic data should be preserved during the archiving period, the complete information package should be identified and archived (e.g., raw data, meta-data necessary to understand correctly the meaning of a record or to reconstruct its source, electronic signatures, audit trails, etc.).