Patient Safety Tip of the Week

October 11, 2011      LEAN in the Lab


In our November 16, 2010 Patient Safety Tip of the Week “Lost Lab Specimens” we discussed performing a FMEA (Failure Mode and Effects Analysis) related to the whole process of handling lab specimens. While you’re doing a FMEA on such an issue you probably should integrate it with redesigning the overall process with LEAN (Toyota Production System) principles. One lab successfully used LEAN principles to redesign processes and improve quality, patient safety and workflow in histology and anatomic pathology (Serrano 2010) at Avera McKennan Hospital in South Dakota.


The Serrano article begins by describing the concepts and tools used in their LEAN redesign project. We usually begin a FMEA by mapping out the entire workflow from beginning to end. In LEAN we develop a “value stream map” that similarly identifies all the steps involved. However, the key to the working with value stream mapping is looking at it through the eyes of the customer(s) and identifying those steps that add no value or are considered waste. The “voice of the customer (VOC)” principle is that your processes should deliver what your customer(s) wants and needs and you need to eliminate those steps that are not of value to the customer(s). Keep in mind that a typical lab has multiple customers – patients, physicians, hospital staff, regulators, and even the staff in the lab itself. Anything that does not add value to the customer(s) should be considered waste (“muda” in the vernacular of LEAN).


The Serrano article nicely describes the various types of waste. One type is defects or time spent doing something incorrectly or inspecting for errors. Overproduction includes not only producing too much but producing it sooner than needed. There is often waste in transportation, that is unnecessary movement of a product within a system. Similarly, there may be unnecessary motion or movement of employees in the system. Waiting for the next work or next activity is a form of waste. Inventory (excess inventory) and overprocessing (doing work not valued by the customer) are other forms of waste. Lastly, waste of human potential by not engaging employees is important.


The Serrano article then shows a spaghetti diagram, another LEAN tool, to show the paths taken by product and employees during processes. For example, this diagram might contain a “map” showing all the key places and items that workers interact with (eg. a reception bin, a refrigerator, accessing station, sterile equipment supply site, processors, etc.). This helps one visually understand the complex movements within the system that may be unnecessary and cause delays or bottlenecks. (Note that one could also borrow from another set of principles and tools in yet another quality improvement approach “Theory of Constraints” or TOC that is especially good at dealing with bottlenecks.)


LEAN then utilizes standardized work, basically best practices to provide guidance to proper performance and order of tasks. Serrano et al. however stress that this still allows professionals to use their own judgment to make certain decisions within that guidance.


Two somewhat related LEAN concepts are “single piece flow” and “first in - first out”. The former concept refers to the need (in a lab) to keep batches to as small a size as possible. The latter refers to making sure that the item which has been in inventory the longest is processed first.


One of the most well-known LEAN principles is “5 S” (sort, straighten, shine, standardize, sustain). These basically say that you need to keep your workspace designed and maintained to promote efficient use. You sort out unneeded items and keep others based on frequency of use. You straighten your workspace to reduce the amount of wasted space. You shine it to keep it neat and clean daily and standardize it so workspaces are consistently organized for anyone who might use them. And you sustain the 4 other “S’s”. (Boy, could my desk use a healthy dose of LEAN’s 5 S’s!!!)


Double-binning is another LEAN concept where 2 identical “bins” are filled with enough supply for a typical 8-hour shift. When one bin becomes empty it serves as a visual cue for a designated person to refill that bin while work continues on the second bin. Another visual cue is “shadowing” where the exact location of equipment or supplies is highlighted so that one can immediately see missing or misplaced items.


And they stress two other LEAN concepts that occur after the redesign. A “kaizen” is a focused small-scale improvement project (timeframe usually 1-2 weeks) typically aimed at addressing bottlenecks or other problems that are seen after the bigger redesign has been implemented. The other is “gembi gembutsu” which means “go and see”. This means that you need to go out into the frontlines to actually observe what is going on and talk to the workers about what is going on. The latter, of course, is known to administrators as “management by walking around” (MBWA) though most of you doing quality improvement and patient safety activities would recognize this is part of your patient safety walk rounds.


Serrano et al. go on to describe what their lab looked like and how it functioned prior to their LEAN project. Not surprisingly, many things had been simply added on randomly without consideration of how they would impact workflows, movement, and efficiencies. (Sound familiar? That’s a problem with adding new technologies to almost every area of the hospital!)


They then describe how they implemented their LEAN project, beginning with the ways they reached out to hear the “voice of the customer” (surveys, questionnaires, interviews, etc.) and how they developed their value stream map (yellow sticky notes, videotaping, etc.). After analysis of all these items they were able to construct a “future state process map”. They then first addressed processes in the supply chain and then receipt of specimens and accessioning, including things like pickup and delivery of specimens, in such a way that they could minimize the need to batch items and facilitate the first in-first out principle.


They go into detail about the redesigned processes in each step. Ultimately, they facilitated a change from a rush/lull workflow to a steady workflow. Outcomes were significantly improved. Overall surgical specimen turn-around times (TAT’s) were reduced 67%, with over 80% of cases being signed out within 24 hours. Staff productivity improved significantly, stress levels were reduced, and satisfaction (both patient and medical staff) reached an all time high.


Mark Graban, in his excellent book “Lean Hospitals” (Graban 2008), also describes a similar dramatic improvement in lab outcomes after a LEAN redesign. St. Paul’s Hospital in British Columbia was able to reduce average TAT by a full day, smooth out the workflow throughout the day for all workers (even transcriptionists now had an even workflow rather than receiving large numbers of batched dictations), improved their quality rating on a 5-point Lickert score from 3.5 to 4.5, and improved employee satisfaction.


One thing missing from these studies are measurements of “hard” patient outcomes. This tends to be a problem in much of the literature on LEAN in healthcare. A recent critical review of LEAN in emergency departments (Holden 2011) found that implementation of LEAN in emergency departments invariably was associated with improved measures of processes (eg. wait times, ER LOS, door-to-needle times, % of patients leaving without being seen, etc.). However, seldom were there reported formal measures of patient outcomes or employee outcomes. Holden also suggests the possibility that publication bias may be in play as well. Nevertheless, Holden also found little evidence of unexpected consequences nor harm from LEAN interventions. Though the employee outcomes were seldom formally measured, numerous studies did comment on the anecdotal increase in employee feeling of involvement and empowerment when LEAN was used.


For those of you new to the LEAN world, the Serrano article provides a great introduction to basic concepts and principles of LEAN. For those of you who are looking for more detail on LEAN in healthcare, wait about a month for the upcoming second edition of Mark Graban’s book “Lean Hospitals”.






Serrano L, Hegge P, Sato B, et al. Using LEAN Principles to Improve Quality, Patient Safety, and Workflow in Histology and Anatomic Pathology. Advances in Anatomic Pathology 2010; 17(3): 215-221,_Patient.7.aspx



Graban M. Lean Hospitals: Improving Quality, Patient Safety, and Employee Satisfaction. Productivity Press 2008



Holden RJ. Lean Thinking in Emergency Departments: A Critical Review. Ann Emerg Med 2011; 57(3): 265-278
















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