The cornerstone of biomarker research is the discovery of clinical variations in biospecimens. However, most variations are subtle and difficult to detect, such as the mutation of a single point in DNA. That’s why researchers need both large datasets and consistently processed biosamples. The integrity of a sample must be protected at every step in the collection, shipping, analysis and storage process –otherwise, the downstream research can go awry.
How can a biosample move from the patient to the repository without any changes that could affect later research? It’s a complicated progression that has to be thoughtfully designed, carefully implemented and well documented. Essentially, a sample moves through four main stages over the course of its life, and smart biobankers think about integrity at every step along the way.
The life cycle of any biosample begins with the patient. Sometimes, samples are collected under controlled conditions, like when a surgeon conducts a biopsy. Other specimens are collected in the field, far away from a hospital or sanitary medical facilities. Even so, it’s important that sampling procedures are kept as constant as possible. One new technology that promises to improve this process is micro-specimen collection for stem cell banking.
Shipping is typically a weak point in the biobanking workflow – because samples are usually placed under the care of another company for transport from the collection site to the biobank. Although the actual shipping is out of your hands, the steps directly before and after can be carefully planned to preserve sample integrity. For example, samples should be packed securely and with enough dry ice or other coolant to keep them at the desired temperature for the duration of the shipment. Remember to note when each sample is shipped so you’ll have a record of the total time spent out of a controlled environment. When samples are received by the shipping group of the repository, they should be logged and processed quickly to the next step in their journey.
Aliquoting and Analysis
This stage in the biobanking process is handled by trained technicians in controlled environments, but it also involves direct sample manipulation and many chances to introduce additional variability. Documentation is key during aliquoting and analysis, and any change to a sample should be meticulously recorded. In addition, results from different analyses must be examined as a whole to ensure expected trends are followed (consistent increase in a biomarker with patient age, e.g.) and aberrant trends can be identified early (such as a correlation of a biomarker with time taken to ship the sample).
The endpoint of any biorepository workflow is long-term storage. But placing a sample into storage doesn’t end integrity concerns. Samples can be retrieved at any time, possibly decades into the future. That means you must protect aliquots against forces that could change biomarkers over time. Freezing and thawing cycles, unintended temperature change and exposure to air and other agents can all have unintended consequences for biomarker concentrations. Many repositories are moving to single-aliquot storage for liquid samples to avoid freeze and thaw cycles and better preserve sample integrity in during long-term storage.
Biomarker research aims to uncover clinical variability between samples – conditions that existed in the patient before sampling and were preserved though the entire biobanking workflow. Additional variability introduced at any stage of the process, whether during sample collection, shipping, aliquoting, analysis or long term storage, can throw off precise measurements of biomarker identification or quantification. Therefore, your goal must be to preserve integrity at every step of the workflow and ensure samples make it from patient to repository in a consistent and well-documented way.
For further information on the journey of a sample in a biobank, check out the article and video at Fisher BioServices’ blog.