Background

Molecular analyses, including RBC typing, epigenetic studies and screening for disease-associated gene alterations, are widely used in blood banks and hospital laboratories. Human genomic DNA (gDNA) isolated from blood samples is the primary material used for these analyses.

Improper storage conditions can result in DNA degradation, which can lead to diminished amplification efficiency and even false-negative results, thus compromising the accuracy and reliability of subsequent genotyping.

Methods

For middle-term storage, a total of 100 gDNA samples derived from 5 blood donors were stored at different temperatures (RT, 4°C, -20°C, -20°C with a single thawing process, and -20°C with thawing every month) for eight months. The level of DNA degradation was assessed by agarose gel electrophoresis, medium-range PCR (1,650 bp), and Agilent Bioanalyzer System.

For long-term storage, each 5 EDTA blood and gDNA samples were stored at -20°C for 3, 5, 10, and 15 years. DNA integrity was compared by agarose gel electrophoresis, medium-range PCR (1,650 bp) and RBC genotyping.

All extractions and purifications were done by magenetic bead-based technology.

Results

gDNA samples stored at 4°C exhibited degradation and decreased amplification efficiencies after eight months. Contrary, high DNA integrity was identified in samples stored at RT and -20°C. Additionally, both EDTA blood and gDNA samples stored at -20°C for 3, 5, 10, and 15 years revealed good DNA recovery and prevented DNA degradation.

Conclusion

In summary, we recommend short and middle-term storage of gDNA samples at RT or -20°C instead of 4°C, as the latter can result in decreased DNA integrity and compromised amplification efficiency.

For long-term storage, a temperature of -20°C is suggested to prevent DNA degradation in EDTA blood and gDNA samples for up to 15 years.

These results may have implications for molecular diagnostic laboratories, where DNA integrity is crucial for additional typing requests and retrospective studies.

Offenlegung Interessenkonflikt:

Im Namen aller Autoren erkläre ich, dass zu den Inhalten der Veranstaltung kein Interessenskonflikt vorliegt.