Nucleic acid sample preparation includes a wide range of extraction and purification techniques that are used to transform a sample from one that can’t be directly analyzed into one that can, thus fitting the specific requirements of the analytical technique being performed downstream. It is highly important to purify and extract your samples when planning on performing quantification and quantitation of nucleic acids.

That’s because purity and yield of the extracted nucleic acids is critical to performance in those downstream applications, which include polymerase chain reaction (PCR)—more specifically, real-time PCR (qPCR)—as well as reverse transcription PCR (RT-PCR) and sequencing. In clinical and research laboratories today, RNA, DNA, and total nucleic acids (total RNA and DNA) are isolated and extracted through both manual and automated techniques.

Manual extraction requires multiple steps, increasing the risk of contamination. It is also considered highly complex, so not every laboratory technician is capable of performing extraction and purification manually.

That being said, another downside to manual extraction is that the entire process is extremely time consuming and labor-intensive, requiring the undivided attention of the technician.

Automated extraction, on the other hand, has many benefits over more traditional manual methods. The most important being the consistency of the isolated nucleic acid. Sample manipulation and reagent use is reduced, significantly decreasing the chance of cross-contamination.

Additionally, automated instruments and systems reduce the overall complexity of extraction and purification, making testing easier to perform by a larger number of scientists.

And while automated extraction instruments have many benefits over manual methods, the cost per test can be drastically higher than manual methods. Automation also only typically makes sense when a high throughput of samples is required.

Knowing your and your team’s exact sample preparation needs is an important step in deciding which method—whether it is manual or automated—as well as which instrument, is right for your lab.

Below we will cover some of the techniques and characterization methods available, as well as the basics of DNA purification.