FAQ: What is the difference between the NEBNext UltraExpress® FS DNA Library Prep Kit and the NEBNext® Ultra™ II FS DNA Library Prep Kit? How do I choose the right one?

NEBNext UltraExpress® FS DNA Library Prep Kit is optimized for streamlined library prep with one adaptor concentration and PCR cycle number used for samples within the recommended input range (10 ng – 200 ng of intact DNA).

NEBNext® Ultra™ II FS DNA Library Prep Kit has been extensively optimized to produce higher library yields at the highest quality. The Ultra II FS DNA Library Prep Kit has more customized conditions based on DNA input amount, more steps and cleanups, a longer workflow time, and a broader input range recommendation (0.1 ng – 500 ng of intact DNA).

Both kits produce high yields of high-quality libraries, but we recommend choosing NEBNext UltraExpress® FS DNA for samples within the stated input amount range, where speed is paramount. We recommend choosing NEBNext Ultra II FS DNA for more complex and precious samples (e.g., low quality or low input).