Manual or Automated?: Choosing the Best Method of Pipetting
Aimee O’Driscoll, BSc, MBA, has a decade of experience as a development chemist and is a seasoned science writer. She can be reached at [email protected].
Lab professionals have been relying on manual pipetting methods for centuries, and they certainly have their benefits, including relatively low-cost equipment and simple techniques. However, with sample sizes decreasing and increased accuracy required, the drawbacks of manual pipetting are becoming more of an issue.
The logical alternative is to consider using automated pipetting equipment that can provide higher throughput and accuracy. But these solutions also come with their downsides and may not be the best option for all applications. So, how do you determine which technique to use? Here, we explore the pros and cons of manual and automated pipetting and explain how to decide which is most suitable.
Having a technician carry out pipetting applications is the norm in most labs, and this method has a couple of key benefits. Waldo Lefever, field pipette calibration specialist at Eppendorf, explains that there is a low up-front cost associated with manual pipetting equipment and very little time is required to train technicians. Lab personnel can easily carry out multiple sample runs and switch between applications with minimal setup required.
“It’s important to consider not only the up-front purchase costs, but also the resources spent in training staff to use the equipment properly.”
That said, there are several drawbacks to manual pipetting, some of which have become more pronounced as demands have changed over time. One key issue is human error. If technicians use inconsistent techniques, there’s a risk of concentration variations. In turn, this can compromise data quality and even prompt costly assay reruns. Consistency and accuracy are increasingly important as modern techniques demand extremely small sample sizes and analytical instruments become more sensitive.
Another downside is the occurrence of repetitive strain injury, with pipetting considered one of the most repetitive tasks in the lab. One study suggests that operating pipettes could double the risk of hand ailments.
Automated pipetting equipment overcomes many of the challenges faced by manual methods. “Assays are performed with significantly more accuracy and precision,” explains Lefever. He notes that this is an especially important consideration in molecular applications that require accurate and consistent sample prep. Automated methods also offer improved speed and often the opportunity to leave equipment running unattended. “Researchers are able to focus on other aspects of their research instead of having to focus on repetitive tasks,” says Lefever.
Automated processes aren’t without their drawbacks, however. These methods are often complex and require lengthy training periods. Apparatus can be difficult to reconfigure between runs and applications are still vulnerable to human error to some extent.
So, how do you know if the benefits of automation outweigh the drawbacks? In cases where accuracy is highly important, the decision is fairly straightforward. Lefever advises that automated pipetting is usually preferable in applications where highly sensitive analytical instruments are being used; for example, next-generation sequencing and qPCR.
In other scenarios, a sensible approach is to weigh the costs of implementing an automated system against the gains. It’s important to consider not only the up-front purchase costs, but also the resources spent in training staff to use the equipment properly. Then compare these to the cost savings realized by increasing throughput and productivity. Also consider the avoidance of other costs such as those associated with assay reruns and personal injury.