Using metal detectors to ward off wayward specimens  

Eye on Innovation

Eye on Innovation features exciting advances taking place at Mayo Clinic Laboratories. This monthly series shines a spotlight on recently developed tests and highlights how Mayo Clinic translates ideas and discoveries into testing resources that improve diagnosis and care for patients across the globe.

The Histology Laboratory in Mayo Clinic’s Department of Laboratory Medicine and Pathology processes more than 350,000 paraffin-embedded blocks every year as lab staff prepare tissue slides for pathologists to evaluate. Each of those blocks represents a patient waiting for answers.

Although lost specimens within the Histology Lab are rare — less than one-half of 1% are ever misplaced — if even one specimen goes missing, it has the potential to be devastating for that patient.

“We’re aiming for zero. One patient block gone is one too many, especially if we’ve taken the only specimen they have,” says Heather Nowacki, the Histology Lab’s pathology accessioning supervisor.

“A small mole, for example, may be all the material available for assessment. If that sample is lost, the opportunity for a diagnosis is lost, as well.”

The effort to safeguard all specimens reaches into every corner of the lab, even the garbage cans. “Our area is busy, with 1,300 to 1,700 paraffin blocks processed every day,” Nowacki says. “When staff get into the groove of their work, it’s possible for something to get knocked off the counter or get lost in the shuffle as things are being thrown away. We never want a specimen to end up in the trash.”

In the past, to ensure that didn’t happen, staff would routinely search the lab trash before it went out, but that approach was neither foolproof nor safe. An alternative was hard to come by, though. Staff tried covering the garbage cans, but that wasn’t a good fit because it slowed down the processing. They considered X-raying the garbage bags before they were removed from the lab, but the equipment was too cumbersome and expensive.

Progress stalled and the project was tabled. But then two members of the Histology Lab staff, Don Hodges and Scott Anttila, approached Elizabeth “Toby” Druffel, the lab’s assistant supervisor, with a unique idea. What about metal? If some type of metal could be embedded in the blocks, then staff could take handheld metal detectors, like the ones used at airports and concert venues, and easily scan the trash bags.

Nowacki and Druffel, along with Samantha Holst, the lab’s technical specialist at the time, thought it over. Why not? Druffel dug into the possibilities. They tried including small metal washers in the blocks, but they were too heavy. Then she found metal stickers. Small, thin squares, the stickers could easily be embedded into the paraffin as the blocks were being made. And reasonably priced, the stickers made the cost-benefit analysis an easy sell.

“We worked with our quality specialist, our lab director, and operations manager, and they all agreed the expense was well worth it to ensure specimen safety,” Nowacki says.

After three months of investigation and validation, and a brief pilot project to confirm that the process would run smoothly, in May 2021, the team implemented it with all 53 technicians in the lab. Today, each tech has a roll of metal stickers at their workstation, and one sticker is embedded in every paraffin block. At the end of a shift, they use the metal detectors to check the garbage bags.

The process has required some adjustments. For example, no excess metal can go into the garbage. Even a stray staple can set off the detectors. With that in mind, all the techs have small containers on their desks for anything else metal, like paper clips or tacks, to go into a separate trash container. Overall, though, the project has proven to be a significant improvement.

“It’s been very successful, and even though it’s a fairly simple process, it’s really quite innovative,” Nowacki says.

“We haven’t seen or heard of any other institution using metal and metal detecting to locate dropped blocks in this way. It was an out-of-the-box idea that we took, and we ran with it. It’s really a great solution: a straightforward process that makes a big difference for our patients.”

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Tracy Will

Tracy Will is a senior marketing specialist at Mayo Clinic Laboratories where she covers innovation, specialty testing, and advances in laboratory medicine. Tracy has worked at Mayo Clinic since 2016.