The Health Risks Caused by Pipetting

Pipetting is a repetitive activity and, as such, can cause serious strain injuries. For those who pipette for less than two hours per day, there is a 20% risk of suffering problems with the hand and shoulder. This increases to a 60% risk for technicians and scientists who pipette for more than two hours per day. The risk of manual pipetting injuries is completely removed with the Andrew robot.

The Reign of the Manual Pipette

Workstation design has been revolutionized by ergonomics. By incorporating an understanding of ergonomics, millions can work all day, every day, without unnecessary strain or pain. To date, the success of adapting the computer workspace for ergonomic consideration has been unmatched in the research laboratory. Unlike a computer workstation, ergonomically adapting a biological research workflow comes with unique challenges.

These include highly variable working environments, experimental limitations to adapting procedures and infrastructure designs based on safety requirements. Although ergonomics is the science of adapting a workplace to the job, in scientific research, the job is often adapted to the science that needs to be done. Over recent years, that job has been changing.

There has been a major shift in which type of research is most common over the past 20 years. Molecular biology and the study of genes, individual cells and proteins was once a niche subject. However, now it has been incorporated into almost all other disciplines including cell biology, biochemistry, medical diagnostic testing, microbiology and especially drug development. This has impacted both the nature of work carried out by Science and Engineering professionals, and the course of drug development.

Nowadays, the manual pipette (Figure 1A) is used for the vast majority of experiments and tests. Using a manual pipette, scientists can mix, move, and aliquot both large and extremely small volumes of liquid samples very precisely. Unfortunately, manual handling of liquids can cause serious ergonomic issues, and the number of hours spent pipetting per year significantly increases the number of users who report pain whilst pipetting (1, 2). Ergonomic pipetting solutions are required to alleviate the issues of with repetition, force and posture that are associated with manual pipetting (2).

A standard manual micropipette being hand-held (A) and operated by Andrew, the pipetting robot (B).

Figure 1: A standard manual micropipette being hand-held (A) and operated by Andrew, the pipetting robot (B).

Several research studies have examined the risk of repetitive strain injuries for laboratory operators, and the results paint a bleak picture. The average time spent pipetting per day is two hours and, even at this level, a biologist or technician is already at an increased risk of repetitive strain injuries. Furthermore, for certain staff, pipetting activities can account for up to 88% of the day (3).

If a standard working week is used as a guide, current pipetting activities are estimated to take up between 1,200 and 1,900 hours per year. This exceeds the identified limit for increased risk of workplace injury significantly (by between four to six times). The productive time lost as a result of repetitive strain disorders is estimated to be 61 billion dollars in the United States, with workplace repetitive strain injury resulting in up to 185 days of work missed per year (4, 5). Although these statistics describe a worst case scenario, even technicians who have not yet experienced debilitating pain may try to avoid pain by adopting compensatory moves within their pipetting technique. This decreases the accuracy of work and wastes valuable samples and resources.

Repetitive Strain Injuries, a Frequent Problem for Pipette Users

Manual pipettes are most commonly handheld and are primarily operated using force applied by the thumb in a very repetitive fashion. Typically, one standard pipetting cycle involves six steps (Figure 2), which are carried out between 6,000 and 12,000 times per day for an average pipette user in the United States, according to NIH studies (6).

Another common addition to this protocol is mixing by pipetting. This involves vigorously depressing and releasing the plunger using the thumb. Each single mixing step includes 60 to 90 repetitive movements every minute. As well as being very repetitive, the force needed to depress and release the plunger using the thumb often exceeds the recommendations for safe working conditions.

The standard calculation indicates that, for each dynamic movement, the force required should be less than 30% of the maximum strength capacity. This means that the force applied in each movement of the thumb should be limited to 2.1 and 3 kg for women and men respectively (6). Although some pipetting steps fall under this limit, depending on the method and pipette used, half of the movements that require force applied by the thumb are above this limit (Figure 2).

Example workflow for one pipetting action (1,5).

Figure 2: Example workflow for one pipetting action (1,5).

For example, the forces required for tip attachment and ejection can be up to 475% of the recommended maximum limit, depending on the method of inserting the disposable tip onto the end of the pipette (1). With forces which can significantly exceed the recommended limits and thousands of replications per day, the risk of repetitive strain disorders for research technicians and scientists cannot be overstated.  The main problem of repetition is not even fully eliminated when using the most modern pipette with ergonomically designed handles and soft plungers.

Body Posture During Pipetting: Another Source of Workplace Injury

Scientists and technicians pipette in order to move and combine very small volumes of liquids precisely. Proper pipetting technique is essential to accomplish this precision and achieve performances indicated by the ISO norm 8655. Generally, this means that the arm must be elevated and extended away from the body for long time periods. Furthermore, the pipette needs to be held vertically and this requires hyperextension and rotation of the thumb and wrist. Altering this posture in any way can lead to a significant reduction in the precision and accuracy of the pipetting process.

In order to accommodate the dimensions of consumables and tips, as well as bins for disposal of contaminated tips, the pipette must also be lifted higher at several steps. Many users adopt awkward positions with their head and neck while dispensing samples into destination tubes in order to enable precise manipulation of the pipette tip into small wells. Moreover, many protocols involve the use of high risk biological samples or dangerous chemicals. This means that the scientist is required to wear uncomfortable protective clothing and gloves and pipette inside biosafety cabinets or fume hoods. This added stress forces users to adopt even more awkward and extended postures (Figure 3).

A technician uses an electronic pipette inside a fume hood.

Figure 3: A technician uses an electronic pipette inside a fume hood.

Approaches to Improve Ergonomics in the Research Lab

Ideally, ergonomic solutions addressing pipetting workflows would combat all of the issues raised by force, posture, duration and repetition. Common recommendations for ergonomically improving the workstation include adjusting posture, changing the height of the workstation (monitors, keyboards or desk being common examples), taking breaks and rotating tasks. Although these solutions are effective in environments like the office, where they can be easily introduced, they are often not cost effective or suitable for a laboratory (Table 1). Several solutions are available to address individual steps in the pipetting workflow effectively (Figure 2), however, none of them simultaneously tackle all areas of concern.

Table 1: Research labs can pose challenges to introducing ergonomic solutions.

Research labs can pose challenges to introducing ergonomic solutions.

One example of a solution that can be introduced to good effect when used upstream of the pipetting workflow is cappers and decappers. These reduce the number of gripping, twisting and pinching movements needed during the day to put on and take off lids. Ergonomic pipettes that require reduced force for accurate plunger depression and enable a more natural arm position can also be beneficial.

Although these improvements address several areas of concern for pipette users, a user survey of several manufacturers identified that, even when these ergonomic features are employed, there is often a trade-off between speed and ease of use for experienced workers (6). Different manufacturers have designed ergonomic pipetting workbenches. However, the design of these is so different to those currently in place that they necessitate a complete overhaul of the research labs infrastructure. They are also not suitable for use with fume hoods or biosafety cabinets.

There is a definite need for cost-effective solutions that address safety cabinets and fume hoods, require minimal adaptation of the current infrastructure and can also be embraced positively by scientists and technicians and incorporated easily into their daily work.

Andrew: a Solution for a Start-to-Finish Ergonomic Pipetting Workflow

Andrew Alliance have introduced Andrew – the best automated liquid handling solution to the ergonomic challenges posed by the pipetting workflow with single channel pipettes (Figure 1B). The Andrew suite of robotic pipetting solutions are anthropomorphic, vision assisted robots for automating the liquid handling process. Andrew is unique in its design, which allows the most commonly found and commercially available pipettes (Gilson and Rainin) and consumables to be used.

Andrew handles these pipettes in the same way that a human operator would and can grab and change pipettes, insert and eject tips, set and change the volume, mix, aspirate, and dispense liquids, all in a very reproducible and accurate way. Andrew can also function inside standard biosafety cabinets and fume hoods and this means that the user does not have to adopt the uncomfortable and risky postures normally required for manual pipetting.

The software is easy to use and requires minimal training, enabling all lab members to design and program pipetting protocols that can then be executed by Andrew. These protocols are fully automated from beginning to end and allow the user to walk away, completely freeing them from repetitive strains on their shoulders and hands. With this all-in-one solution, laboratories no longer need to adjust the infrastructure of the lab, hire additional technicians to enable task rotation, or replace all manual pipettes.

The problems occurring from working in safety cabinets and fume hoods are also eliminated. By reducing the risk of repetitive strain injuries for scientists and technicians, Andrew keeps them healthy and happy, enabling them to focus productively on what really matters: Science.


  1. Bjorksten et al., 1994. App Ergonomics (25) 88.
  2. David & Buckle, 1997. App Ergonomics (28) 257.
  3. Asundi et al., 2005. Hum Factors (47) 67.
  4. McGlothlin et al., 1995. Health Hazard Evaluation, pp. 13. United States NIH for Occupational Safety and Health, Frederick, Maryland.
  5. Stewart et al., 2003. JAMA (290) 2443.
  6. Litchy et al., 2011. Work (39) 177.

About Andrew Alliance S.A.

Andrew Alliance is an independent, privately financed company, based in Geneva, Boston and Paris. The company was created in March 2011.

Andrew Alliance is dedicated to advance science by working with scientists to create a new class of easy-to-use robots and connected devices that take repeatability, performance, and efficiency of laboratory experiments to the level required by 21st-century biology.

Start with meeting customer needs, end with customer feedback.

Andrew Alliance delivers solutions that are focused on customer needs, both today and in the future. Our products are manufactured to the highest standards, using a range of carefully selected, proven, and sustainable technologies, that ensure both high performance and reliability. We actively seek continuous customer feedback, in order to guarantee the best possible design outcomes.

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Last updated: Oct 19, 2020 at 8:12 AM


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