Patient Safety Tip of the Week
October 9, 2007
Errors in the Laboratory
Last week
a 35 year old woman from Long Island, New York appeared on Good Morning America
to discuss her tragic case that resulted from misidentification of a biopsy
specimen. She had a double mastectomy after a tissue sample from a lab based in
New York came back positive for breast cancer. Doctors later told her she did
not have breast cancer and "never did", she said on the TV program.
Apparently there was a "lab mixup".
The New
York State health department reported that the biopsy sample had been
mislabeled by a technician at a pathology laboratory, probably because the
technician was handling more than one specimen at a time. The report said the
technician admitted to his supervisors that he "occasionally cut corners
by batching" and did not always verify patients' initials when labeling
them.
A very
similar case is noted in “Meeting the Joint Commission’s 2007 National Patient
Safety Goals”1. And an article about the current case in Newsday2
includes the description of a second recent case where a woman unnecessarily
received radiation therapy for a cancer she did not really have. Undoubtedly
there are many more comparable examples. We could not find any published error
rates for misidentification of biopsy specimens but one study looking at
surgery in an outpatient clinic or a hospital operating room found 4.3 surgical
specimen identification errors in every 1000 cases (and about 60% of those
errors were in biopsies) 3. Rates for incorrectly identifying
hospitalized patients prior to collection of blood specimens have been found to
be as high as 6.5%4.
The Joint
Commission standard on patient identification requires use of at least 2
patient identifiers (neither of which is the patient’s location). In addition,
all containers must be labeled in the presence of the patient. And for
laboratories there must be a process in place to maintain the sample’s identity
throughout the preanalytical, analytical, and postanalytical processes.
However, laboratories should not automatically reject specimens lacking the 2
discrete identifiers because some samples may be irretrievable (such as biopsy
specimens). In such cases the laboratory should have written guidelines on how
to handle these specimens and the laboratory report should include a cautionary
statement indicating the lack of complete identification. Importantly,
prelabelling of collection containers is not to be done. Since specimen
collection is often performed by personnel outside the laboratory, Joint
Commission stresses education and inservicing of all personnel involved plus
appropriate monitoring/auditing of the processes.
For Joint
Commission-accredited hospitals the Joint Commission standards apply to the
laboratory even if the laboratory is not specifically accredited by Joint
Commission. However, a growing number of procedures with pathological specimens
are being performed outside the hospital setting, not only in ambulatory
surgery centers but in physician offices. The latter are often sending
specimens to private or commercial laboratories that are not subject to the
Joint Commission standards. Most such laboratories are otherwise accredited or
certified (eg. by CAP or CLIA). When multiple organizations are involved the
preanalytical, analytical and postanalytical phases, we suspect the likelihood
of error is even higher.
While
there is a lack of systematic reporting on such incidents, much can be gleaned
from individual case reports. In one such case5, a pathologist noted
a discrepancy among specimens submitted from several sites on the same patient.
Specifically, the histological appearance suggested that specimens labeled “wrist”
and “back” had been transposed and one of them showed a melanoma. When the
pathologist contacted the physician who performed the biopsies, it turned out
the patient was the physician’s spouse and that the procedures had been
performed on a Sunday when the office was closed and no support staff were
available. The specimens had been place in formalin-filled biopsy bottles,
prelabeled with the biopsy sites and the requisition sheets were labeled only
the following day by the nurse.
Another
case6 involving transposition of prostate biopsy specimens from two
patients used a detailed root cause analysis (RCA) that uncovered multiple
contributing factors and suggested several improvements to processes. These
included not only steps to ensure a “one-by-one” accessioning process but also
improvements in dictation and transcription and what to do once such an error
is identified. Note that this lab used molecular testing to confirm the
transposition of specimens and correctly match up the specimens with the correct
patient. See below for more on use of DNA techniques in laboratory
identification of patients.
Some
circumstances that may increase the likelihood of specimen mislabeling include:
·
Multiple specimens on the same patient
·
Multiple specimens on different patients being
transported at the same time
·
Multiple specimens being accessioned at the
laboratory at the same time
·
Specimens arriving near closing deadlines
·
“Rush” specimens
·
Procedures (eg. biopsies) being done outside of
normal hours
·
Procedures being done in site other than
hospital operating room
·
Specimens coming from a different physical
location
Potential
solutions include barcoding (of patient and biopsy bottles), ensuring adequate clinical
information and descriptions accompany the specimens, strict one-by-one
accessioning of specimens, and regular auditing of processes.
In cases
where misidentification of specimens is suspected, some labs have used DNA
testing to verify the correct match of patient to specimen. In fact, some have
gone as far as to propose universal use of DNA polymorphic microsatellite
analysis to confirm patient identification before invasive treatement in
patients undergoing biopsies such as prostate biopsies7.
So what
should a patient do? You should ask such questions as: Where will my
biopsy specimen be evaluated? Is that lab accredited? By whom? Will any other
specimens be being sent along with mine? How and when will I be notified of the
result? (And if the specimen is being sent to a lab other than a hospital-based
lab, we recommend you also inquire about any financial arrangements between the
physician and the lab.)
What
should a physician do? He/she should ensure that all staff in his
office/facility fully understand the processes involved in specimen collection,
identification, and transport. The specimen handling should be done with the
same diligence that one uses during surgical timeouts. He/she should have a
good understanding of the steps that the laboratory takes to ensure patient
identification is maintained throughout. He/she should always provide a good
clinical description of the patient and what is being looked for on the
specimen(s). When pathology reports note something unexpected, call the lab to
discuss the possibility of misidentification and discuss whether a
molecular/DNA technique to confirm correct identity should be considered.
Also
remember that misidentification of a laboratory specimen impacts two patients
(in today’s index case, not only did the patient receive unnecessary treatment
but there obviously was a second patient who did have cancer and we are not
told if she received appropriate and timely treatment). So it is
imperative in such cases to double check to see whether two errors have
occurred.
By the
way, you’d be surprised at how often errors take place in cases where a
physician is treating one of his/her own family members. The scenario above,
where a procedure is done after-hours and without proper personnel present, is
one we have seen on numerous occasions. The AMA has guidelines on physician
treatment of family members and we feel strongly that the anecdotal evidence of
errors in such circumstances is an even more cogent reason for physicians not
to treat their own family members.
Update: See also our November
16, 2010 Patient Safety Tip of the Week “Lost
Lab Specimens”, which also contains some other good articles on
mislabeling and mixups of surgical specimens (Layfield 2010, Lippi
2009, Nakhleh
2003, Valenstein
2004, Astion 2006).
References:
1. Makary MA, Epstein J, Pronovost PJ et al. Surgical specimen
identification errors: A new measure of quality in surgical care. Surgery 2007;
141: 450-455 http://www.surgjournal.com/article/S0039-6060%2806%2900624-6/abstract
2. Grayson A (ed.), Meeting the Joint Commission’s 2007 National Patient
Safety Goals. Oakbrook Terrace, IL: Joint Commission Resources. 2006: pp. 13-14
5. Jukic DM. Pathologist as the Final Quality Assurance Officer, or “The
Buck Stops Here”. Pathology Case Reviews 2005; 10: 88-94
6. Dhir R, Condel JL, Raab SS. Identification and Correction of Errors in
the Anatomic Pathology Gross Room. Pathology Case Reviews 2005; 10: 79-81
7. Suba EJ, Pfeifer JD, Raab SS. Patient Identification Error Among
Prostate Needle Core Biopsy Specimens – Are We Ready for a DNA Time-Out?
Journal of Urology 2007; 178: 1245-1248
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