BACKGROUND: In many cohort studies, biological specimens are being stored without specific plans for analyses. In the Norwegian Mother and Child Cohort Study biological specimens (DNA, plasma, and whole blood) are stored on 96-well plates and as a result may undergo multiple freeze-thaw cycles. METHODS: To explore the impact of multiple freeze-thaw cycles on chemical constituents, we conducted a quality control study using pooled EDTA-plasma. Over a two-year period, samples stored at -80 degrees C were subjected up to 100 freeze-thaw cycles. Specimens were analyzed in triplicate for sodium, cholesterol, triglycerides, vitamin E, aspartate aminotransferase (AST), and free fatty acids. We assessed the percent change of analyte concentration from the values for the first freeze-thaw cycle, because this is the baseline for all stored specimens. RESULTS: With the exception of free fatty acids, there was little change over the first 10 freeze-thaw cycles. A majority of analytes showed no significant changes until 30 freeze-thaw cycles. After 30 freeze-thaw cycles, the largest percent change was observed for free fatty acids (+32%), AST (+21%), and triglycerides (-19%). CONCLUSIONS: Human plasma can go through several freeze-thaw cycles before analysis without influencing sample integrity for the selected analytes.
Modern biomedical research requires access to high quality specimens of human tissue with or without extensive clinical annotation. Multiple types of organizations have developed to supply human tissues to support biomedical research. These organizations follow different models including the specific models of 1) prospective collection, 2) tissue banking, and 3) tissue collection associated with clinical trials as well as the model of 4) a tissue resource that incorporates features of the other models. These types of organizations devoted to supplying tissues for research have chosen different goals to meet the different tissue and informational needs of the investigators to whom they supply tissue. In order to provide high quality tissues to support research, all models should rely on a strong quality assurance program with extensive quality control of the tissues being provided to support research. In addition to facilities which collect, process, store and provide tissues, the need for a rigorous QA program applies to all resources and infrastructures used to support biomedical research. The UAB Tissue Collection and Banking Facility which provides human tissue to support biomedical research has been functioning and developing since 1979. To our knowledge, similar programs in providing tissues from animals are less developed, but could easily follow the models which UAB and other institutions providing human tissues have established, including the approaches of UAB and others to QA and QC. This manuscript reviews the current concepts of QA and QC in use in organizations supplying tissue to support biomedical research as well as new approaches in QA and QC that have been proposed.
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：