Does Size Matter? Comparison of Extraction Yields for Different-Sized DNA Fragments by Seven Different Routine and...

Area of Science:

• Molecular Biology
• Clinical Diagnostics
• Virology

Background:

• Nucleic acid extraction is critical for PCR-based microbial detection.
• Existing methods show quantitative differences and lack of commutability, hindering standardization of viral load assays.
• Small DNA fragments (<200 bp), including cell-free DNA (cfDNA), are present in plasma and may contain viral DNA.

Purpose of the Study:

• To compare extraction yields across 11 commercial methods, including 4 new cfDNA isolation kits.
• To evaluate the impact of extraction methods on DNA fragment yield across a size range (50–1,500 bp).
• To assess the consistency and efficiency of small DNA fragment recovery.

Main Methods:

• Evaluated 11 commercially available nucleic acid extraction methods.
• Extracted DNA fragments ranging from 50 to 1,500 bp.
• Quantified DNA fragment yields using droplet digital PCR.

Main Results:

• Demonstrated wide variability in extraction yields across methods and instruments.
• Observed particularly inconsistent quantitative results and poor yields (<20%) for 50- and 100-bp fragments.
• Two of four cfDNA kits showed slightly higher and more consistent yields for small fragments.

Conclusions:

• Significant need for further evaluation of nucleic acid extraction yields across platforms.
• Existing methods exhibit poor extraction efficiency for small DNA fragments.
• Inconsistencies and low yields of small DNA fragments require further investigation for clinical virology applications.