Biostorage and Quality Control for Human Peripheral Blood Leukocytes

Background: Peripheral blood leukocytes (PBLs) are the main source of DNA in blood samples. A common protocol is to store buffy coat specimens for future DNA isolation, and such samples may remain in frozen storage for years. However, the currently available methods to maintain buffy coat specimens can be optimized for better quality and cost efficiency. Study Design and Methods: Seventeen donors (aged 24–34 years) were enrolled in this study. Initially, five centrifugal speeds were chosen to examine the distribution of PBLs in the cell layer; the buffy coat was then harvested to evaluate the cell quantity and viability after storing at 4°C for various times. Finally, the buffy coat was isolated, snap frozen, and kept at −80°C for 1 hour, 1 week, or 4 weeks until the DNA was extracted. Agarose gel electrophoresis and multiplex PCR were used to verify DNA integrity and amplifiability. Results: There was a linear positive correlation between the amount of fresh PBLs and the DNA yield. At least 70% of PBLs w...