Danger: You Might be Pipetting Yourself Out of a Job

You might be proud of your pipetting skills (if not, check this article on how to stop pipetting errors from ruining your experiments) and be churning out data faster than a liquid handling robot, but beware… you might also be pipetting yourself out of a job. I almost did. Pain due to pipetting is common. Hand pain is reported by 90% of people that pipette in continuous sessions of an hour or more.¹ Women that pipette for more than 300 hours a year are at much higher risk for hand and shoulder ailments than other women.² 300 hours per year is only around 75 minutes per working day! Ignoring repetitive strain can lead to permanent nerve damage, like carpal tunnel syndrome and repetitive strain injury (RSI), and end a bench science career. So, you need to know about the ergonomic pipetting technique before you feel any pain. I didn’t even notice any pain until I suddenly found myself unable to hold a tube against a vortexer. I had been overcompensating for an unfamiliar and sub-functional set of pipettes by loading my tips with too much force. Repeatedly jamming pipette tips onto my micropipette ended up giving me a crippling shoulder injury and an enormous physical therapy bill. But preventing this kind of problem doesn’t have to be expensive.

Tips For Staying Pain-Free:

1) Keep your limbs in neutral

Keep your wrist in a relaxed, neutral position. A neutral wrist position is in line with your forearm, not bent forward, backward, or sideways. Avoid raising your elbows; they should be relaxed and close to your body. Your forearm should be at a right angle to your body. Don’t lean on your elbows or rest your forearm on the edge of the bench–unless you don’t value your nerves.

2) Don’t forget the rest of your body

Don’t twist up like a pretzel: make sure your bench or hood has space for your legs when you work sitting down. If people want to store something where your legs are supposed to go, tell them they can pay for your chiropractic bills. Keep your back in a relaxed and chair-supported position, don’t hunch your shoulders, or crane your neck.

3) Adjust your working height

Make sure your chair height is adjusted so that you can work with your forearm at a right angle. If your chair is too low, you’ll end up with your forearms raised all day. Also, you must remember that the correct height depends on the task , so be prepared to adjust throughout the day. For example, you’ll need your chair to be at one height for work done at benchtop level and at a different (probably higher) height if all your samples will be kept in an ice bucket (which elevates the samples above the benchtop).

4) Be aware of the length and intensity of your pipetting sessions

The longer the pipetting session, the greater the chance of injury.¹ You should take frequent, short breaks every 20 minutes during long periods of pipetting. Taking breaks not only prevents strain and RSI thumb, but also allows you to refocus on your posture and technique.

5) Organize your workspace

Plan the location of your tips, samples, and waste container, you can minimize overreaching and awkward hand positions. For example, in a biological safety cabinet, you should arrange your workflow to avoid crossing contaminated items over clean items. If you are right handed, then you’d work from left to right—keeping the clean cultures on the left, what you’re currently working with in the center, and discarding waste on the right.

6) Minimize pipetting force

Pipettes vary in the amount of force they require to operate. If you are having trouble staying pain-free, then you should consider changing models. The most important considerations are the force required to dispense liquid and eject the tip, pipette weight, and the position of your hand during operation. In general, electronic pipettes require little force to operate compared to manual pipettes, although they can also be heavier. Don’t forget brand choice for your tip—mismatched tips and pipettes sometimes require more force to load and eject decreasing accuracy and forcing you to use improper pipetting techniques.  You can also look in to more ergonomic pipettes. Finally, don’t forget that there are other repetitive manual tasks that you need to watch out for. The other time that I’ve had to deal with an expensive repetitive strain injury was after writing my PhD thesis on a laptop. That was when I knew it was time to go back to pipetting Further Reading

1. David, G and Buckle, P (1997). Applied Ergonomics, 28(4):257–62
2. Björksten, MG, Almby, B and Jansson, ES (1994). Applied Ergonomics, 25(2):88–94