Mitigating Risk and Improving Patient Safety


In the current pathology multi-functional technical process (a combination of manual and automated technical tasks and alternating batch/single unit processing), the incidence of errors is a constant cause for concern. As laboratories consolidate and assume larger workloads, the potential for errors to arise becomes more prevalent.

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Preface Part 2

Today’s hectic laboratory environment is driving the need to increase productivity while at the same time improving quality and patient safety. To meet these new demands, leadership must rethink lab management and double down on its efforts to create a robust quality controlled and managed process that will reduce the incidence of mishandling specimens prior to stained slide review.

Creating a new process requires the collaboration of Histotechnicians (technical) and Pathologists (professional) as well as the use of instruments (automation) to lay the foundation for the three pillars of pathology quality: 1. Process Improvement/Control, 2. Defect Reduction, and 3. Improved Patient Quality/ Safety. Caution must be used to ensure collaboration remains balanced and not heavily weighted on one side of the team or process. The goal is to identify, reduce and improve the process, reduce risk of contamination and misinterpretation, and satisfy patient requirements for safe and quality results.

The following discussion will address all steps in the technical process where tissue contamination can occur and must be controlled, while focusing on Gross Dissection, Embedding and Microtomy. Reduction or elimination of the possibilities for extraneous tissue contamination, whether the task is automated or performed manually, on a single unit, or a batch, can be achieved and provides superior quality results. It is important to note that not all technical tasks have the same level of risk, and that time, effort and cost must be taken into consideration in order to successfully control the process and reduce contamination while performing routine technical tasks.


The high degree of variability in the currently accepted technical pathology process allows for several opportunities for defects and/or contamination. The technical pathology process must be broken down into individual tasks to develop an integrated multi-point quality control checklist. Key critical processing steps include Gross Dissection, Tissue Processing, Paraffin Embedding, Microtomy and Staining, which, without proper control, can become problematic and opportunities for cross contamination of extraneous tissue fragments (“floaters”) can arise. Any uncontrolled process can produce extraneous contamination that can reduce the productivity of the lab and pathologist, leading to increased patient risk and production costs. According to a study conducted by CAP Q-Probes, the largest study to date on the currently accepted process for reviewing slides, misinterpretation due to slide contamination is rare, and extraneous tissue causes diagnostic difficulty at a rate of 0.1%-to 1.2%. Furthermore, while no level of contamination is desirable, not all pathologists agree that there is a problem. Laboratories do not have a standardized process to identify, eliminate and control the technical process; and vendors have multiple automation solutions for single unit and batch. These issues aside, as we move further toward adopting precise medical processes, any defect, including “floaters,” can become increasingly problematic when trying to verify and validate the test results associated with each slide reviewed.

The challenge for today’s pathology laboratory is to develop a process that increases individual responsibility for checking and identifying defects, detecting areas where contamination may occur and can be eliminated, using available quality control/assurance tools to quantify the level of risk and limits of the controlled process (i.e. Levy-Jennings chart) and apply resources and efforts to improve the quality of results. Further development and implementation of automation is essential to quality improvement and risk reduction, but integration into the existing production process, cost effectiveness, ability to reduce variance, ease of implementation and acceleration of overall quality improvement must all be evaluated. Without addressing these considerations, disruptions to the process may be created. Automation cannot fix all the problems and defects in the process, but process control will improve the quality of the current slides.

Principle of Process

Create a robust multi-point QC (quality control) checklist for each critical task. Assessment is the first and most important step to eliminating defects/errors and developing the controlled process. An inferior production process will result in unacceptable production results. QC Level 1 involves a compliant continual inspection of areas where there might be opportunities for errors. Marshal your efforts to get the best results and improvement. Each small improvement provides additional time for further inspections and to create a quality improvement loop. The end goal is to implement a QC inspection at all stages and steps of the process. At QC Level 2, evaluate and implement the optimal automation for the process. Each time automation is selected, invest the savings in time and hands-on activities back into the quality improvement process. Now you can perform root cause analysis and make additional positive changes to the production process. QC Level 3 entails the continued evaluation of automation, increasing productivity and tightening the quality improvement loop to further reduce the opportunity for defects/errors.

All QC activities contribute to controlling the production process and serve as a guide in the process, enabling maximum effort to be applied and creating better results. When using the limited resources to maximize effort, pay close attention to the voice of your primary customers (pathologist and patients) while continually communicating with technicians. This must be a continuous group discussion with group participation; anything less will affect progress toward improvement. Successful QC/QA (quality control/quality assurance) activities are essential for allowing the pathologists to have a validated slide review and concentrate on the patient. Individual participation and responsibility in all quality activities leads to compliance, continued collaboration and process improvement.

Create a Better QC Process

QC Level 1

Integrate multi-point quality control into each step of the production process

Concentrate on the CRITICAL TASK control

Create lab process standardization

QC Level 2

Implement and integrate automation where appropriate

Apply automated processes

Increase QA activities

QC Level 3

Stratify workforce

Increase automation production

Real time technologist involvement in QC/QA activities

Critical Process Tasks


Proper fixation is a critical pre-step for the following process

Control the fixation time once specimens arrive in the lab

Create minimum and maximum fixation times for all tissue types, tissue thickness in cassette and fixative solutions

Gross Dissection

Ensure the equipment is cleaned between each specimen/case (forceps, scalpel)

Gloves are changed frequently during the grossing of small cases and after each large case

Only one specimen is permitted on the grossing station at a time

All specimens <0.5cm use a single use pipette

Secure specimens <0.5 cm in the cassette

Friable specimens permitted extra fixation time

Change fixation and reservoir daily

Visual management (multiple checks for compliance during task)

Document, evaluate and improve

Tissue Processing

Complete fixation before processing (set lab standard for min/max)

Rinse cassette basket 2-3 times in fresh fixative, using slow agitation, prior to placement on processor

Consider small batch processing

Rotate and change solutions/wax by cassette count

Visual management (multiple checks during maintenance/QC activities)

Document, evaluate and improve

Paraffin Embedding

Ensure the equipment is cleaned between each cassette (forceps, work stage, tissue holding tank)

Use gloves and change frequently

Single cassette embedding (only one cassette on work stage at a time)

Never embed under/incomplete processed tissue. Stop and reprocess sample

Visual management (multiple checks during maintenance/QC activities)

Document, evaluate and improve


Ensure the equipment is cleaned between each cassette (forceps, knife stage, work area)

Use gloves and change frequently

Avoid using aerosol cooling spray (creates airborne movement of small tissue fragments)

Avoid using water in cassette cooling/holding tray (creates cross-contamination of tissue fragment on cassette)

One slide in work area at a time (slides remain in packaging or another container, remove slide after cutting then mount)

Never cut under/incomplete processed tissue (tissue fragments will release from dried slide) Stop and reprocess sample

Clean slide racks frequently to remove debris

Use care when placing slide in racks to prevent cross-contamination from slide to slide

Visual management (multiple checks during maintenance/QC activities)

Document, evaluate and improve

Floatation Waterbath

Ensure water receptacle is cleaned daily and add acceptable number of blocks cut to reclean and change water (i.e. build-up of paraffin on edge; friable tissues cut; any debris noticed below surface of water)

Use distilled or deionized water only

Additives in the water bath can affect the results of staining

Visual management (multiple checks during maintenance/QC activities)

Document, evaluate and improve


Thoroughly clean all reagent receptacles and slide racks daily and as needed due to volume

Use multi-point QC

- H&E Stain

Create and use production multi-tissue control slide (determined by Medical Director i.e. 3-5 of highest volume tissue types processed)

Run control slide:

Prior to start with new reagents

Addition of any solution(s)

Rotation of any solution(s)

If high slide volume; determine number of slides run that that require replacement or rotation of solutions

Stop all production when running control slide

Validate acceptable quality for all manufactured reagents (i.e. determine acceptable number of slides to run before setting QC checks)

- IHC/Special Stains

Type of controls used to be determined by Medical Director (i.e. endogenous tissue background; no primary antibody; isotype; absorption; tissue type)

Daily production multi-tissue control slides (number determined by Medical Director; groups of antibodies or key antibodies by volume) before production use each day

Visual management (multiple checks during maintenance/QC activities)

Document, evaluate and improve


Defect/error reduction and process improvement must be the primary goal of all QC/QA activities, yet allocation of time and resources continue to be the challenge. Before starting any process change (i.e. implementing automation, starting/changing QC/QA activities), there must be a documented method to check and confirm compliance. Defect/error identification management— whether manual or automated, single unit or batch processing – will be successful using a multi-point QC checklist and controlling the technical process. Frequency of QC/QA activities will vary depending on volumes (i.e. tissue samples, cassettes, slides), but all QC/QA activities must provide time for evaluation and correction before resuming the production process.

Any and all improvement activities applied to the pathology multi-functional technical process will result in better utilization and easier implementation of automation. All QC/QA activities require compliance and immediate troubleshooting – do not wait for the end-point QC when the pathologist reviews the slides.

Controlling the technical process will produce superior slide results by reducing tissue contamination. Apply efforts and resources to the steps that have the highest level of opportunity for tissue contamination and risk: Gross Dissection; Embedding; Microtomy.

Reduction of “floaters” on stained slides starts at the beginning of the technical process, and reducing the number of opportunities for tissue contamination at all critical steps will result in improving the quality of the stained slide delivered for the pathologist’s review. Lack of or reduction of quality activity throughout the process can result in tissue contamination on a stained slide, whether using open or closed instruments.

Creating a laboratory specific standard (in light of the lack of established industry standards), coupled with controlled and robust QC/QA processes does produce a reduction in the opportunity for and the actual number of defects/ errors in the multi-functional process. Stop, consider and discuss before making any process change; investigate and develop check/evaluate/correct activities that are laboratory specific; and work within the current process.

Some of the most effective strategies for reducing tissue contamination on the stained slides and improving the overall quality of the process include: developing a controlled process from the start to finish (each step is critical); using multi-point QC/QA activities (without an end-point QC); creating personal responsibility and participation; and visually managing and documenting processes (cannot manage without documentation).


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