Background: and aims UK Biobank is a large prospective study in the United Kingdom to investigate the role of genetic factors, environmental exposures and lifestyle in the causes of major diseases of late and middle age. It involves the collection of blood and urine from 500 000 individuals aged between 40 and 69 years. How the samples are collected, processed and stored will have a major impact on the future scientific usefulness of the UK Biobank resource. A series of validation studies was recommended to test the robustness of the draft sample handling and storage protocol.
Methods: Samples of blood and urine were collected from 40 healthy volunteers and either processed immediately according to the protocol or maintained at specified temperatures (4 degrees C for all tubes with the exception of vacutainers containing acid citrate dextrose that were maintained at 18 degrees C) for 12, 24 or 36 h prior to processing. A further sample was maintained for 24 h at 4 degrees C, processed and the aliquots frozen at -80 degrees C for 20 days and then thawed under controlled conditions. The stability of the samples was compared for the different times in a wide variety of assays.
Results: The samples maintained at 4 degrees C were stable for at least 24 h after collection for a wide range of assays. Small but significant changes were observed in metabonomic studies in samples maintained at 4 degrees C for 36 h. There was no degradation of the samples for a range of biochemical assays after short-term freezing and thawing under controlled conditions. Whole blood maintained at 18 degrees C for 24 h in vacutainers containing acid citrate dextrose is suitable for viral immortalization techniques.
Conclusions: The validation studies reported in this supplement provide justification for the sample handling and storage procedures adopted in the UK Biobank project.