Six Sigma project reduces analytical errors in an automated lab.
Six Sigma project reduces analytical errors in an automated
The North Shore-LIJ Health System is the third-largest nonsectarian health system in the country.
Created in 1998, the health system's laboratory model consists of a strategically located core lab
that uses total laboratory automation and offers consolidated testing, a rapid response lab in each of
the system's 18 hospitals, a standardized standardized
pertaining to data that have been submitted to standardization procedures.
standardized morbidity rate
see morbidity rate.
standardized mortality rate
see mortality rate.
?LIS LIS - Langage Implementation Systeme.
A predecessor of Ada developed by Ichbiah in 1973. It was influenced by Pascal's data structures
and Sue's control structures. A type declaration can have a low-level implementation specification.
, and standardized laboratory instrumentation. The core laboratory performs over 3.5 million tests
annually for a client base comprised of hospitals, long-term care facilities long-term care facility
See skilled nursing facility. , clinical trials, physician offices, and reference testing. The lab performs
approximately 65% of the routine testing for the network as well as all microbiology
Scientific study of microorganisms, a diverse group of simple life-forms including protozoans, algae,
molds, bacteria, and viruses. , esoteric es?o?ter?ic??
a. Intended for or understood by only a particular group: an esoteric cult.?See Synonyms at
b. , molecular diagnostic, and reference testing.
As part of the laboratory's ongoing performance-improvement process, changed results had been
measured for years. Although the average percentage of changed results was consistently below 1%
in the three main areas of the laboratory--hematology, coagulation coagulation?(k??g'y l?`sh?n), the
collecting into a mass of minute particles of a solid dispersed throughout a liquid (a sol), usually
followed by the precipitation or , and chemistry--the administration had noted that eight analytical
process failures had occurred in the first half of 2003, resulting in the correction of reported values
that affected multiple patients at one time.
The problem was sporadic sporadic?/spo?rad?ic/ (spo-rad?ic) occurring singly; widely scattered; not
epidemic or endemic.
1. Occurring at irregular intervals.
2. ; there was no clear solution; and correcting the issue would help achieve the core lab's goal of
improving patient care, increasing customer satisfaction, and boosting staff morale. The core lab's
administration believed that reducing the number of failed analytical processes was a worthy goal
for a Six Sigma Not to be confused with Sigma 6.
Six Sigma is a set of practices originally developed by Motorola to systematically improve processes
by eliminating defects. A defect is defined as nonconformity of a product or service to its
specifications. ?project. A multidisciplinary mul?ti?dis?ci?pli?nar?y??
Of, relating to, or making use of several disciplines at once: a multidisciplinary approach to
teaching.??team of technical management, information systems staff, and physicians assembled to
tackle the problem using the Six Sigma define, measure, analyze, improve, and control (DMAIC
DMAIC Define, Measure, Analyze, Improve, Control
DMAIC Design, Measure, Analyze, Improve, Control (5 stages of Six Sigma Quality Improvement and
Six Sigma methodology
Six Sigma, a focused, high-impact process, uses proven quality principles and techniques to reduce
process variance, and seeks to confine errors to 3.4 defects per million opportunities In process
improvement efforts, defects per million opportunities or DPMO (or nonconformities per million
opportunities (NPMO)) is a measure of process performance. It is defined as
?(DPMO DPMO Defects Per Million Opportunities (Six Sigma)
DPMO Deployment Process Modernization Office
DPMO Defense Prisoner of War (POW)/Missing Personnel (MP)?Office ). Six Sigma relies on rigorous
statistical methods and implements control mechanisms in order to tie together quality, cost,
process, people, and accountability, and begins with an understanding of customer requirements
and values (referred to as voice of the customer). Once these are defined, Six Sigma's process
enables the identification of factors critical to customer satisfaction. The processes involved in these
critical factors are then analyzed an?a?lyze??
tr.v. an?a?lyzed, an?a?lyz?ing, an?a?lyz?es
1. To examine methodically by separating into parts and studying their interrelations.
2. Chemistry To make a chemical analysis of.
?and measured. Improvement strategies are focused on the vital "X." The Six Sigma goal is to reduce
both variance and control processes in order to assure compliance with the critical specifications.
Defining and measuring the process
During the define phase, the Six Sigma team developed a high-level process map (see Figure 1), with
the initial step being preparation of the analyzers for use and the final step being release of the
result. The project's scope covered the process from sample placement on the analyzer
1. a Nicol prism attached to a polarizing apparatus which extinguishes the ray of light polarized by
2. ?to the point at which the result was released in the LIS. A defect was defined as the need to
change a result for any reason after verification.
Also during the define phase, the Six Sigma team needed to convince lab employees that further
reduction of changed results was necessary, even though the average changed-result rate was
already less than 1%. To accomplish this, the team used change acceleration process tools, such as
the threat/opportunity matrix, to demonstrate the benefits of reducing changed results and the
disadvantages of maintaining the current changed-result rate. For instance, reducing changed
results would increase lab efficiency, improve staff performance and morale, and boost market
share. Maintaining the current rate of changed results would ultimately diminish the core lab's
reputation, leading to a loss of revenue and decreased staff morale.
[FIGURE 1 OMITTED]
In the measure phase, the Six Sigma team used operational definitions and the lab supervisory staff
to perform measurement-system analysis. Because the lab already operated at a high sigma SIGMA -
A scientific visual programming environment from NASA.
http://fi-www.arc.nasa.gov/fia/projects/sigma/. ?level, the measurement system had to be 100%
accurate for reproducibility reproducibility?Lab medicine? The degree of agreement among repeated
measurements of a particular parameter, presented in terms of a standard deviation or coefficient of
variation of the results in a set of measurements ?and repeatability. The team had to ensure that any
variations were due to the process, not the measurement system. In order to obtain this type of
accuracy, the team developed operational definitions to classify clas?si?fy??
tr.v. clas?si?fied, clas?si?fy?ing, clas?si?fies
1. To arrange or organize according to class or category.
2. To designate (a document, for example) as confidential, secret, or top secret. ?errors: procedural,
autoverification, sample, clerical, mechanical, and unknown. With the aid of logic trees, the team
refined these definitions five times to ensure all errors were classified consistently so that
repeatability and reproducibility were 100%. Statistical analysis using the Six Sigma methodology
revealed that the lab operated at a 4.8 sigma level.
For the period of May 2003 through July 2003, the laboratory corrected 585 test results out of
1,645,975 results reported. The DPMO was 355. One of the Six Sigma tools--the stakeholder
stakeholder?n. a person having in his/her possession (holding) money or property in which he/she
has no interest, right or title, awaiting the outcome of a dispute between two or more claimants to
the money or property. ?analysis--aided in developing a strategy to gain support for the project from
moderately opposed individuals and helped identify those individuals likely to be involved in the
process who could serve as resources for the team.
[FIGURE 2 OMITTED]
Analyzing and improving procedures
In the analyze phase, the Six Sigma team developed its aggressive goal of reducing analytical errors
by 35% to a DPMO of 230 and a sigma score of 5.0. As the process moves toward a sigma level
between 5 and 6, eliminating defects without eliminating the human factor becomes increasingly
Graphical analysis using Pareto charts (see Figure 2) indicated 86% of the defects could be
attributed to two types of errors: Whereas 52% of the defects were procedural errors committed by
employees while reviewing results, 34% of the defects were the result of autoverification errors by
the LIS. This discovery was enlightening en?light?en??
tr.v. en?light?ened, en?light?en?ing, en?light?ens
1. To give spiritual or intellectual insight to: ; SOPs (standard operating procedures standard
operating procedure?Medtalk A technique, method or therapy performed 'by the book,' using a
standard protocol meeting internally or externally defined criteria; a formal, written procedure that
describes how specific lab operations are to be performed. ) were not accomplishing their intended
Six Sigma focuses on process, not people. Before the analysis, the team members had been
convinced the culprit was something beyond the core lab's control, such as unacceptable specimens
received from the rapid response labs or from the outreach Outreach is an effort by an organization
or group to connect its ideas or practices to the efforts of other organizations, groups, specific
audiences or the general public. ?physician's office. The lab had established SOPs for all operations,
yet the staff was having difficulty making key decisions when it came to releasing analytical results.
The analysis of variance (ANOVA anova
see analysis of variance.
ANOVA?Analysis of variance, see there ) proved this vital "X" to be statistically significant. The null
hypothesis null hypothesis,
n theoretical assumption that a given therapy will have results not statistically different from
n ?that all types of analytical errors are the same was rejected because the p-value 0.001 was less
than 0.05; thus, the team could conclude that a statistical difference in the number of defects existed
among the different error categories.
The team utilized tools--like failure mode and effect analysis (FMEA FMEA Fehler-M?glichkeiten & -
einfluss Analyse (German: Failure Mode & Effect Analysis)
FMEA Failure Modes & Effects Analysis
FMEA Florida Music Educators Association
FMEA Florida Municipal Electric Association )--to break down the very complicated process into
individual steps: potential failure modes, effects, severity, cause, occurrence, control, and detection
(Figure 3), so its members could look at key drivers, or "Xs," in the process. Data for each step was
analyzed graphically and tested mathematically for statistical significance.
One vital "X" was that the majority of errors occurred on two analyzers: general chemistry and
Branch of medicine concerned with the nature, function, and diseases of the blood. It covers the
cellular and serum composition of blood, the coagulation process, blood-cell formation, hemoglobin
synthesis, and disorders of all these. . The team drilled down, utilizing the five why's tool and the
voice of the customer from the technical staff. By developing an assessment tool, the team identified
deficiencies in the staff training program. Staff trained by the vendor or lab supervisors scored 40
points higher on competency COMPETENCY, evidence. The legal fitness or ability of a witness to be
heard on the trial of a cause. This term is also applied to written or other evidence which may be
legally given on such trial, as, depositions, letters, account-books, and the like.
???? 2. ?tests than peer-trained staff. The result was obvious. Ongoing basic training needed to be
performed to stress analyzer maintenance, troubleshooting Troubleshooting is a form of problem
solving. It is the systematic search for the source of a problem so that it can be solved.
Troubleshooting is often a process of elimination - eliminating potential causes of a problem. , and
recognition of analyzer "flags."
[FIGURE 5 OMITTED]
To reduce the number of procedural errors in the improve phase, a simplified result-review guideline
guideline?Medtalk A series of recommendations by a body of experts in a particular discipline. See
Cancer screening guidelines, Cardiac profile guidelines, Gatekeeper guidelines, Harvard guidelines,
Transfusion guidelines. ?tool was provided to technologists as an aid in the critical decision-making
process used to validate test results (Figure 4). The autoverification process was modified to capture
real-time suspect flags for CBC (1) (Cell Broadcast Center) See cell broadcast.
(2) (Cipher Block Chaining) In cryptography, a mode of operation that combines the ciphertext of
one block with the plaintext of the next block. ?orders; results that required review were held by the
LIS. The LIS team designed software that enabled real-time analyzer-result monitoring for chemistry
analyzers, complete with an audio alert for notification of potential problems.
In the control phase, the Six Sigma team implemented a plan that incorporated individual and
moving range charts for monitoring corrected results. The control plan enabled the team to
determine the method for monitoring frequency, alert flag, action, and specific accountability for
each of the key variables in the process. The DPMO for corrected results is now monitored on a
monthly basis (see Figure 5). The Six Sigma metric has become part of the lab's quality-management
program. Real-life examples of analyzer printouts and flag results are used to assess staff
competency on an ongoing basis.
At the end of the control phase, the process went from a 4.8 sigma level to a 5.0 sigma level. Using
the chi-square test chi-square test:?see statistics. , the team was able to demonstrate a statistically
significant decrease in the number of corrected results. The technical area of the core lab has
experienced a 20% growth in volume from the completion of the project in December 2003 to
present. The Six Sigma team turned the project over to its process owner The process owner is the
person who co-ordinates the various functions and work activities at all levels of a process. This
person might have the authority or ability to make changes in the process as required, and manages
the entire process cycle to ensure performance ?in January 2004. Since that point, the department
has operated at a sigma level of 5.0 or higher and was at a 5.2 sigma level as of October 2004. This
project produced no direct financial impact. As chairman of the Department of Laboratories, Dr.
Thomas Sodeman observes, "The error-reduction project was undertaken because it was the right
thing to do."
The Six Sigma DMAIC methodology has many advantages. It is a rigorous process that engages
front-line employees in process redesign re?de?sign??
tr.v. re?de?signed, re?de?sign?ing, re?de?signs
To make a revision in the appearance or function of.
re . It utilizes data and the voice of the customer to determine the factors that are most critical to
quality. Controls and accountability are put in place to ensure the process remains efficient. Finally,
this approach provides lab personnel with the tools to take a good process and make it even better.
Figure 3. Failure mode and effect analysis
Rank process steps--narrows vital Xs with risk priority number
Process step/input Potential failure effects
What is the process Potential failure mode What is the impact on the
step and input under In what ways does the key output variables
investigation? key input go wrong? (customer requirements)?
Autoverification Rule manager not Results released without
Report result SOP not followed Wrong result
Sample prep Label needs Delay in testing, or
repositioning redraw needed
Shift communication Tech leaves early or Satus of testing site
arrives late unknown
Review results Staffing issues Results get delayed
Review results LIS problems Results get delayed
Instrument prep Printer jams, no Delay in testing
paper, toner out
Run QC QC out of range Testing delayed while
Review results Instrument problems Results get delayed
Gather work LIS or CLAS down and Delay in testing
Instrument startup Out of reagents Delay in testing
Analyze specimens Samples not assayed Results delayed
Process step/input Potential causes
What is the process What causes the
step and input under key input to go
investigation? SEVERITY wrong? OCCURRENCE OCCURRENCE
Autoverification 8 LIS overburdened 5 5
Report result 6 Tech error 3 3
Sample prep 7 Phiebotomist's 5 5
Shift communication 8 Tech does not
inform anyone of 6 6
Review results 2 Stress 5 5
Review results 5 LIS overburdened 5 5
Instrument prep 2 Tech distracted 5 5
Run QC 2 QC not properly 2 2
Review results 2 Training 3 3
Gather work 2 Schedules not 2 2
Instrument startup 2 Startup not done 1 1
Analyze specimens 2 Orders delayed 1 1
in getting to
Process step/input Current controls
What is the process What are the existing controls
step and input under and procedures (inspection and
investigation? test) that prevent either the
cause or the failure mode? DETECTION RP N
Autoverification 5 200
Report result Exception report 8 144
Sample prep 3 105
Shift communication 2 96
Review results 8 80
Review results 3 75
Instrument prep Observation 2 20
Run QC SOP 5 20
Review results 2 12
Gather work 2 8
Instrument startup Checklist 3 6
Analyze specimens 1 2
Figure 4. Error classification guide
Test Detail Range Review Critical
low high low high low high
ALB 0.1 10.0 1.5 6.5
ALKP 3 1000 3
AMY 4 1500 4
BALKP 3 1000 3
BUN 1 150 1 130 90
CA 0.2 16.0 6.0 10.5 7.0 13.0
CHOL 3 800 30 500
CL 60 140 75 130
CO2 10 45 10 40 10 45
CPK 4 2300 4
CREAT 0.1 25.0 8.0
DBILI 0.1 10.0 15.0
GGT 3 1200 3
GLU 2 750 45 500 45 450
HDL 8 150 15
K 1.5 10.0 2.0 7.0 2.9 6.0
LDH 5 1000 50
MG 0.1 6.0 0.5 4.0
NA 80 180 120 155 125 155
PHOS 0.3 20.0 1.0 8.0
SGOT 4 800 4
SGPT 4 400 4
TBILI 0.1 30.0 5.0
TP 0.2 15.0 4.0 9.0
TRIG 4 1000 15 400
URIC 0.2 25.0 1.0 20.0
By Nancy Riebling, MBB MBB Men's Basketball
MBB Master Black Belt (Six Sigma)
MBB Medical Biochemistry and Biophysics (Karolinska Institutet, Stockholm, Sweden)
MBB Make Before Break , MS, MT(ASCP ASCP?American Society of Clinical Pathologists. ), and
Laurel Laurel, cities, United States
1 Town (1990 pop. 19,438), Prince Georges co., central Md., about halfway between Washington,
D.C., and Baltimore; patented in the late 1600s, inc. 1870. ?Tria, MS, SC(ASCP)
Nancy Riebling, MBB, MS, MT(ASCP), firstname.lastname@example.org, is the director of Operational
Performance Solutions and a Six Sigma Master Black Belt for the North Shore-LIJ Health System,
Laurel Tria, MS, SC(ASCP), Itria@nshs.edu, is project manager for the Core Lab and a Six Sigma
Certified See certification. ?Black Belt. The Six Sigma program is part of the Center for Learning &
Innovation under the health system's Corporate University.
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