Background: UK Biobank is a large prospective study in the UK to investigate the role of genetic factors, environmental exposures and lifestyle in the causes of major diseases of late and middle age. Extensive data and biological samples are being collected from 500,000 participants aged between 40 and 69 years. The biological samples that are collected and how they are processed and stored will have a major impact on the future scientific usefulness of the UK Biobank resource.
Aims: The aim of the UK Biobank sample handling and storage protocol is to specify methods for the collection and storage of participant samples that give maximum scientific return within the available budget. Processing or storage methods that, as far as can be predicted, will preclude current or future assays have been avoided.
Methods: The protocol was developed through a review of the literature on sample handling and processing, wide consultation within the academic community and peer review. Protocol development addressed which samples should be collected, how and when they should be processed and how the processed samples should be stored to ensure their long-term integrity. The recommended protocol was extensively tested in a series of validation studies. UK Biobank collects about 45 ml blood and 9 ml of urine with minimal local processing from each participant using the vacutainer system. A variety of preservatives, anti-coagulants and clot accelerators is used appropriate to the expected end use of the samples. Collection of other material (hair, nails, saliva and faeces) was also considered but rejected for the full cohort. Blood and urine samples from participants are transported overnight by commercial courier to a central laboratory where they are processed and aliquots of urine, plasma, serum, white cells and red cells stored in ultra-low temperature archives. Aliquots of whole blood are also stored for potential future production of immortalized cell lines. A standard panel of haematology assays is completed on whole blood from all participants, since such assays need to be conducted on fresh samples (whereas other assays can be done on stored samples). By the end of the recruitment phase, 15 million sample aliquots will be stored in two geographically separate archives: 9.5 million in a -80 degrees C automated archive and 5.5 million in a manual liquid nitrogen archive at -180 degrees C. Because of the size of the study and the numbers of samples obtained from participants, the protocol stipulates a highly automated approach for the processing and storage of samples. Implementation of the processes, technology, systems and facilities has followed best practices used in manufacturing industry to reduce project risk and to build in quality and robustness. The data produced from sample collection, processing and storage are highly complex and are managed by a commercially available LIMS system fully integrated with the entire process.
Conclusion: The sample handling and storage protocol adopted by UK Biobank provides quality assured and validated methods that are feasible within the available funding and reflect the size and aims of the project. Experience from recruiting and processing the first 40,000 participants to the study demonstrates that the adopted methods and technologies are fit-for-purpose and robust.