On-demand printing in a world of developing technology

On-demand printing in a world of developing technology

The emerging technology of on-demand printers can offer significant benefits to histology laboratories and pathology procedures, while also facilitating error reduction, explains Lauraline Winter.

On-demand cassette and slide printers have risen in popularity as the modernisation of histology spreads, and as the technology develops so does the print quality, production speed and the amount of data a small two-dimensional barcode can contain. Though some pathologists may steadfastly disagree with their necessity, it cannot be denied that errors from handwritten labelling are unfortunately unavoidable due to human nature. All it takes is a smudge of handwriting, a misheard instruction, or simply a misspelled name which can have catastrophic consequences for patients, physicians, and the reputation of the hospital or laboratory. 

Healthcare systems and regulating organisations have taken steps to focus on process excellence at all stages of the care continuum, and one solution to improve accuracy is a reliable printing solution, coupled with the ability to track specimens as they make their journey through the lab. Many pathologists that have not yet implemented such technologies face a crossroad, to remain using the ‘analogue’ procedures they have become accustomed to or to utilise new and emerging technologies to better optimise LEAN workflows and reduce potential errors. 

Labelling errors and the domino effect

For people working in the medical profession handwriting has often been a source of ridicule, where to some it is a difficult to decipher ‘chicken scratch’ that seemingly only fellow doctors, chemists or scientists can understand. Though many would argue the truth of this stereotype to vary from different medical professions, the fact remains that any and all handwritten notes and labels are subject to mistakes due to human error.

Conditions also exist in labs that can make errors simply unavoidable. Slides and cassettes are frequently exposed to harsh chemicals. These chemicals can sometimes erode the writing on labels applied to slides before the staining begins, and handwritten cassettes can quickly become unreadable. The risk of errors is increased significantly when attempts are made to label slides and cassettes manually, or match samples with printed labels that have been produced away from the work area. This type of procedure can result in the incorrect label being applied, or illegible handwritten slide labels and cassettes being matched to the wrong patient. The result of this has a destructive knock-on effect, as the integrity of patient data is imperative. 

A study by the College of American Pathologists in 2010 looked at mislabelling rates across 136 institutions for eight weeks or until 30 errors were identified. It found errors in labelling equally across different pathology stages, with a rate of 25.5% for blocks, 27.7% for slides, 27.1% were cases and 19.8% were specimens. In most cases the error was usually detected quite quickly, and steps were taken to rectify it immediately after, however, this does not change the fact that errors occurred and are statistically unavoidable. 

At least 6 different opportunities for transcription error present in standard histopathology procedure.

Lord Carter’s review of NHS Pathology Services in 2006 stated: “Identification error is the single most important cause of patient safety incidents in pathology.” As illustrated, there are many mislabelling opportunities present through the various stages of pathology.

The use of a 2D barcode for tracking purposes is proving to be more commonplace in laboratories and as the scanning technology advances further, high-quality cassette printers with a print resolution of 300 dpi results in an easy-to-read and superior-quality print. This again has the knock-on effect of reducing errors, as the print is legible, and barcodes scan quickly and correctly.

The error rate for manual matching is approximately 1 in 300, whereas for 2D barcode scanning, it is between 1 in 10.5 million to 1 in 612.9 million. Barcodes take 0.3 to two seconds to scan as opposed to human time of six seconds. Total elimination of errors may be unfeasible. However, error-free label printing is achievable. Direct-to-slide and cassette printing technology has advanced greatly within the past few years, and laboratories can now take advantage of this to improve internal efficiency and reduce the chances of specimen misidentification.

What can on-demand printers do?

On-demand cassette printers produce labelled cassettes quickly and accurately with the push of a button. As technology has developed these printers have become smaller, faster, and smarter. The newest designs incorporate large touch screens for ease of use and laboratory staff can print the exact number of slides and cassettes they require, when and where they need them. The ability to print in colour also assists laboratories to operate more efficiently by removing the need to track inventory of cassettes and slides in varying colours.

The printers are designed to be small so multiple workstations can have their own dedicated printer. When laboratory staff send a print job to a centralised printer, there is a danger of staff picking up the wrong slide or cassettes. Having the ability to use a small desktop-sized printer eliminates these issues. Cassette printers utilise chemical and heat-resistant inks that can withstand xylene, alcohol, stain, heat, and chemicals, resulting in a reduction of errors due to harsh laboratory conditions. The software of cassette printers has also greatly developed, laboratories can now work with customisable software that enables them to utilise templates for the collection of necessary data and generate data for laboratory information systems.

When selecting a cassette and slide printer, it’s imperative that laboratory managers ensure they select a model that will help the laboratory meet its efficiency and error reduction goals. Features to look for are efficiency, easy-to-use operation with a small footprint and high-quality output. Durability is also an essential component, slide and cassette printers should be robust enough to weather harsh laboratory conditions, be capable of tolerating disinfection from standard hospital cleaning products, and of course be water resistant. 

Another key feature to bear in mind when selecting a printer is cartridge design, cartridges that facilitate quick changes will be beneficial to laboratory staff as they can easily swap out cartridge types to accommodate varying cassettes (such as micro biopsy, biopsy, and routine) and slides. There are also options available for multi-hopper cassette printers, with a carousel style design of several hoppers, ideal for laboratories with a busy workload printing many cassettes. 

The Caltagirone Example

In 2019 the Gravina Hospital in Caltagirone, Sicily, which is a large hospital that collects cases from seven different hospitals in the Catania area, made the transition to a digital workflow. Prior to this transition, the Caltagirone pathology laboratory utilised a non-tracked workflow, using hand-written blocks and slides, submitting paper requests, and manual assembling and delivering cases and glass slides to pathologists. Furthermore, the layout of workspaces and offices in the department was counter-productive and disorganised, affecting the linearity of the workflow. 

To remedy these conditions, various changes were made, all with the intention to increase automation. At the grossing stage, a camera device was introduced to take pictures at the grossing bench and capture material in the block. At sectioning, barcodes were automatically printed onto glass slides rather than hand labelled and archiving was also improved, with better storage trays to facilitate barcode scanning and online tracking. 

The Sicilian laboratories faced some resistance to change at first and continued to lack an adequate tracking system; glass slides and tissue blocks were handwritten, and transcription mistakes were consistently made. Not all workflow steps were appropriately checked, and varying, and redundant paperwork accompanied the workflow from the accessioning to the assembling and delivering of the glass slides. However, this analogue workflow was eventually abandoned and a new paperless 2D barcode tracking system was fully integrated.

The workflow had the new system implemented throughout, from accessioning to diagnosis. 2D barcodes were found to be more successful to 1D as they are less space-demanding, more easily applied to convex surfaces of tissue containers, and in general they are less prone to scanning issues. Furthermore, laser printers for blocks were introduced with the goal of obtaining a permanent mark of the barcode on surfaces. 

To promote this new automation procedure, the Lean philosophy was followed, many laboratory procedures that had been performed in a repetitive manner were simplified. These achievements were possible due to the widespread use of 2D barcodes, as now that could be fully tracked, reducing the opportunity of human error and double handling. 

Gravina Hospital cassette and slide organisation before and after adopting the use of cassette and slide printers.

The Caltagirone pathology department had a yearly workload of 8,182 histological cases with a total of 42,245 corresponding slides, and within a year all activity of the laboratory had been modified from a non-tracked workflow to an automated procedure incorporating several new technologies. The benefits were widespread, repetitive tasks were eliminated, slides and cassettes were able to be tracked throughout the entire pathology procedure, and the entire workplace became more streamlined and organised.

In teaching staff to use these new instruments and procedures, the required training was far less than expected. As staff members were computer literate, training to use a new printer or machine didn’t take more than a short tutorial session and two to five days to get accustomed to using it. 

Although, to completely benefit from the advantages of on-demanding printing the process needs to follow an optimisation of resources, time, space, instruments etc, the Lean workflow must be adhered too, and appropriate training of the new technology is key.


There is nothing of a higher importance than patient safety, which is why laboratories frequently assess their standard procedures and processes to make sure they are managing potential risks in the most effective way possible. Specimen misidentification is a reality that must be faced, it can happen to anyone through a chain reaction of events, and on-demand printers aim to be the remedy to this problem. 

The ability to contain patient information within a 2D barcode revolutionises the way specimens are tracked in the laboratory; it eliminates the need for unnecessary paperwork as all the relevant data can be contained directly on the cassette or slide.

If the correct printer is selected, with a high-quality output, consistent and clear printing, and a reliable barcode scanning for tracking purposes, then the positive ripple effect this has proven to have in laboratories becomes astoundingly obvious. 

Using the Caltagirone example as the litmus test for the viability of on-demand cassette and slide printers, it’s clear that they are a vital tool for pathologists. These pieces of equipment will only continue to advance in capabilities, further pioneering the way for the most sophisticated histopathology technology. As author Sukant Ratnakar said: “Our future success is directly proportional to our ability to understand, adopt, and integrate new technology into our work.”