Repetitive Motion Injuries and Ergonomics in the Histology Laboratory

Histologists are commonly ranked among jobs that were “most damaging to your health.” The sources of injury in histology laboratories include handling harsh chemicals like xylene; sitting at workstations that require viewing sections, slides, and screens for long periods of time; slips and falls from the buildup of wax and other chemicals on the floor; and operating instruments that require repetitive motions by operators.

Quote about impact and cost of injuries in histology laboratories.

The last item in that list – operating instruments that require repetitive motions by operators – can be the most painful and costly to histologists and histology laboratories. The effects of repetitive motion and other injuries can be very serious for the histologist. In addition to numbness and/or pain, injuries can inhibit future work, as well as activities outside of work. Treating the injury may require surgery, which causes additional risk, pain, and likely missed work. As a result, injuries can cause decreased employee satisfaction and lower quality of life. The same effects can be attributed to more random injuries due to slips and falls.

Injuries costly for laboratories that are already under pressure to lower costs and are presented with vacancies and imminent retirements. This guide focuses on repetitive motion injuries in the histology laboratory, specifically around microtomy, and how they can be prevented. By reading on, you’ll learn:

What are common repetitive motion injuries in the histology laboratory?

Many of the long-term stresses of working in a histology laboratory are musculoskeletal disorders due to cumulative trauma, also called repetitive motion injuries (RMIs). RMIS are caused by utilizing the same muscles and tendons repeatedly to perform the same task. Examples of RMIs experienced in the histology laboratory include carpal tunnel syndrome, tennis elbow, deQuervian’s Disease, trigger finger, neck and back pain, and others.

Carpal Tunnel Syndrome

“Carpal tunnel is the number one cumulative trauma disorder that happens in histology,” says Allison Eck, HTL(ASCP)CM, QLS, AHI(AMT), Lead Tech at Doylestown Hospital in Doylestown, PA. “It’s not a matter of who’s going to get it, but when you’re going to get it due to the nature of repetitive wrist motion in histology.” In the histology laboratory, movements that cause carpal tunnel syndrome can be attributed to turning the microtome handwheel, as well as repetitive actions performed during embedding, coverslipping, as well as typing. Symptoms of carpal tunnel syndrome include numbness, tingling, weakness, and pain in the thumb and first three fingers.

Tennis Elbow

Tennis Elbow is another injury often attributed to microtomy. Caused by repetitive wrist movements, tennis elbow is inflammation of the tendons that join the forearm muscles on the outside of the elbow. Histologists that are troubled with tennis elbow experience pain from the outside of the elbow to the forearm and wrist, as well as stiffness, weakness, or numbness.

Tendonitis of the Hand: deQuervian’s Disease and Trigger Finger

Tendonitis is a general term for inflammation of tendons. Hands and fingers are especially susceptible to tendonitis in histology laboratories because of repeated gripping of the handwheel, transfer of sections to the waterbath, and pressing buttons. deQuervians Disease is characterized as tendonitis at the side of the wrist and base of the thumb. It can be painful when the thumb is moved or twisted. Trigger finger is characterized by a finger locking in bent position due to inflammation narrows the space within the sheath that surrounds the tendon in the affected finger. It can be caused by gripping hard handles on equipment, such as that found on the microtome hand wheel.

Back and Neck Pain

Histologists can spend much of their day sitting, often looking at portions of work stations that can be at an awkward angle. This occurs while working at a microtome, laying sections and ribbons on a water bath, working at a grossing station, and watching a computer screen. This can cause pain in the lower or upper back, as well as neck strain.

What repetitive motion injuries can be attributed to microtomy?

Repetitive motions in both the technical and administrative duties of histologists can result in carpal tunnel syndrome as well as hand, arm, and shoulder injuries. Histologists are especially susceptible to repetitive motion injuries due to workflow steps and equipment that have not been automated.

Sources of Repetitive Motion Injury around Microtomy.

Microtomy is an under-automated workflow step and a major source of injury for histologists. Motorized microtomes exist, allowing users to press a foot pedal or a button instead of turning a handwheel, but histologists historically operate them manually. One study determined that an average of 41 revolutions per block was required to produce a single slide using a manual microtome. If the median productivity for a full time histologist is 6433 blocks per year, the average histologist would turn the fine advance wheel over 260,000 times per year using a manual microtome if only producing one slide per block. Other sources estimate this number to be more than 500,000 times a year. Over a long histology career, this large number of turns to the handwheel makes injuries inevitable. Read more about why you should make the switch from manual to motorized microtomes.

An often-overlooked source of additional injuries at the microtomy station is section transfer. Section transfer from the blade to the water bath, and then onto slides requires repetitive fine motor movements that can cause injury to the fingers, hands, arms, and shoulders. Eck comments, “Tendonitis is another major issue that comes from microtomy, from the fine motion of picking up ribbons and from pinching forceps.” Read more about repetitive motion injuries around microtomy.

Furthermore, examining sections on the water bath to determine when they have sufficiently relaxed and which sections are most appropriate to mount on to slides, can cause neck and eye strain.

How can repetitive motion injuries be prevented in microtomy?

Automated laboratory equipment, such as automated coverslippers and strainers, can relieve histologists of repetitive tasks that can cause injury. The use of motorized microtomes is highly recommended across the industry, and specifically by the National Institute of Environmental Health & Sciences (NIEHS). A new area of automation that can further reduce the risk of repetitive motion injuries is the automation of section mounting. By removing the manual steps of section floating and placement on a slide, repetitive motions can be substantially decreased.

How can the Aquaro ASM reduce histology laboratory injuries?

The Aquaro ASM™ (Automated Section Mounting) aims to reduce the incidence of injuries by automating the processes of microtomy, specifically section transfer and section mounting. The Aquaro ASM interfaces with microtomes to transfer sections from the blade to slides using a gentle water stream. Prior to placing a section on a slide, the Aquaro ASM relaxes the section by exposing it to warm water at a temperature and for a time programmed by the histologist. See how the Aquaro ASM works.

Aquaro ASM Automated Section Mounting

The Aquaro ASM can reduce the incidence of injury around microtomy in several ways. Without the need to transfer ribbons from the blade to the water bath, histologists will be relieved of the potentially injurious repetitive use of tweezers and other small tools. This will reduce the risk of tendonitis and other injuries to the wrist and arm. When paired with a motorized microtome, the Aquaro ASM triggers the microtome to cut sections, including during facing and between levels, and mounts or discards sections without the intervention of the histologist. With this advantage, users are less likely to utilize motorized microtomes in a manual manner, reducing the incidence of carpal tunnel syndrome and other repetitive motion injuries due to cranking the handwheel. Utilizing the Aquaro ASM to float sections at a temperature and for a time programmed by the user results in a uniform relaxing of the section which minimizes wrinkles and folds. Torn sections are identified with the instrument’s section sensor and are not mounted, giving more useable sections. As such, histologists do not have to hover over the water bath examining sections, instead checking slides in a more ergonomically favorable position after the run is complete. Lastly, by removing the sources of repetitive motion injuries in microtomy, the Aquaro ASM may also allow previously injured histologists to perform microtomy again.

By reducing the buildup of paraffin on the floor, the Aquaro ASM can decrease the incidence of slips and falls. Sections are directly cut on to flowing water, reducing the chance of paraffin drifting to the floor. In addition, the water channel eventually flows to a filter that collects excess paraffin due to facing, between levels, or other sections that are not mounted which further ensures a clean microtomy environment.


Histology laboratories remain one of the “most damaging jobs to your health,” but some the sources of danger are avoidable. Microtomy especially has room for improvement through automation. The Aquaro ASM can reduce injury by encouraging the use of motorized microtomy, reducing repetitive fine motor actions due to transferring sections to the water bath and slides, and decreasing the incidence of strain when looking at sections on the blade and water bath. The Aquaro ASM will significantly improve work life in the laboratory by reducing repetitive motion injuries, decreasing the risk of slips and falls, and overall by making the laboratory safer for the histologist.