Cases & Commentaries
Urine a Tough Position
A 22-year-old unmarried woman came to her
doctor’s office worried that she might be pregnant. Although
she did not want to have a baby at that time, she stated that she
would carry the pregnancy to term if she were pregnant.
The patient collected her own urine sample and
placed it in the specimen cabinet, which opens into the laboratory.
A urine specimen already placed in the cabinet by a different
patient had not yet been labeled and processed by the lab
technician. Five minutes later, the physician was informed that the
pregnancy test was negative. The physician conveyed this result to
the patient, much to her great relief.
After the physician left the room, he was
informed that the two specimens had likely been switched. The other
urine sample belonged to a diabetic patient; the technologist
suspected a mix-up after a urine dipstick on that sample indicated
elevated glucose. Both patients were asked to resubmit urine
samples; in fact, the patient was pregnant.
The physician was placed in the awkward position
of informing the patient that the samples had been switched, and
appropriate sympathetic counseling was made more difficult.
Some might argue that this case is a near miss as the
technologist caught the mistake relatively quickly—before the
patient even left the office. However, this case does represent an
error and preventable adverse event, because the patient
experienced some emotional harm. Certainly, the outcome of this
error could have been far worse. It was fortuitous that the
laboratory technician realized that the samples had been swapped
due to the presence of glucose. One could imagine this error
remaining undiscovered until the patient presented months later
with clinical signs of pregnancy. In the interim, the patient might
have acted in ways potentially harmful to the pregnancy.
Little is known about errors and adverse events
in the outpatient setting. Approximately 8%-9% of adverse events
occur in physicians’ offices.(1)
Recent studies have examined adverse drug events in ambulatory
and adverse events related to the inpatient–outpatient
Hundreds of millions of laboratory tests are ordered annually in
primary care practices, yet little is known about how often
laboratory errors occur in primary care.
Laboratory testing can be broken down into three
phases: pre-analytic (test ordering, specimen collection, and
handling), analytic (test performance), and post-analytic (result
handling and communication). Because of improvements in and
automation of laboratory procedures, most laboratory errors occur
during the pre-analytic and post-analytic phases of the testing
process. A literature review found that laboratory errors in the
pre-analytic phase ranged from 32%-75% of all errors.(6) In
another study, 39% of lab errors involved misidentification of the
requested tests, the requesting doctor, and/or the
another article describing the epidemiology of lab errors prompting
incident reports, pre-analytic errors occurred in 71%, with
specimen transportation being the most common.(8)
There are few published studies of laboratory
error rates in the outpatient setting. An outpatient study
published in 1996 (9)
assessed 124 primary care clinicians in 49 practices in the United
States and Canada. Clinicians were asked to report any
irregularities in the laboratory testing process during a 6-month
period. A total of 180 laboratory problems were detected, for a
crude frequency of 1.1 laboratory problems per 1000 patient visits.
Of 180 reported problems, 49 impacted patient care (27%). Of these,
10 (6% of total) had a significant effect on patient care.
Problems detected in the pre-analytic phase were most common
(55.6%) and specimen handling and collection problems were the most
common overall (33.9%), similar to the urine mishandling case
presented here. Given the known low yield of self-reporting
this study’s results probably represent only the "tip of the
Unlike in the inpatient setting, where caregivers
typically procure and transport laboratory specimens, in the
outpatient setting patients are often responsible for collecting
and transporting their own samples. This is a potential set-up for
patient identification errors or specimen mishandling errors. In
this case, the patient placed the urine specimen in the cabinet
adjacent to the lab. Often, patients deliver throat swabs, lab
requisitions, x-rays, and other clinical items to various sites of
outpatient care. Therefore, verification of patient identification
and proper labeling of specimens, requisitions, and clinical
information in general is crucial. However, this process often
breaks down. Sample labels are often handwritten with minimal
information (eg, "Smith" when there could be multiple Smiths in the
clinic that day). In addition, samples may not be labeled at all,
or may be labeled only after the patient has left.
Primary care practices and testing facilities
should take a proactive process redesign approach to the issue of
laboratory errors, particularly those associated with pre-analytic
or specimen handling errors. Techniques such as failure modes effects
analysis (FMEA) (11)
can help to map out the laboratory specimen process and all the
potential ways in which failures (or errors) can occur. Then,
clinical staff can collaborate to design fail-safe mechanisms for
ensuring proper specimen identification and handling during the
pre-analytic phase of testing. The Joint Commission on
Accreditation of Healthcare Organizations (JCAHO) has mandated that
two forms of patient identification should be used for blood
and this should apply to any kind of lab specimen. This patient
verification should occur at the time a specimen is labeled, and
the label should include at least two identifiers (ie, full name
and birthdate). In addition, specimen collection bottles should be
labeled before the patient provides the sample. Labels should be
legible and should never be left in a window or deposit area
without a label. Clear guidelines for this specimen process should
be created and processes audited to ensure compliance.
Technology can of course help with some of these
issues. Using preprinted labels assures completeness and
legibility. However, before a printed label is affixed to a sample,
confirmation with the patient is still necessary. Barcode
technology is another way of tracking samples and linking patients
accurately to their samples.
Another key issue is that outpatient clinics and
labs should have methods to capture these errors when they occur,
even if only via a voluntary reporting system. This can allow
tracking and trending of errors and further facilitate process
redesign based on the types of errors identified. Only through
aggressive error identification and subsequent action can we ensure
a more error-free health care system in the future.
K. Gandhi, MD, MPH
Director of Patient Safety
Brigham and Women´s Hospital
1. Weingart SN, Wilson RM, Gibberd RW, Harrison
B. Epidemiology of medical error. BMJ. 2000;320:774-7.[ go to PubMed ]
2. Gandhi TK, Weingart SN, Borus J, et al.
Adverse drug events in ambulatory care. N Engl J Med.
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3. Gurwitz JH, Field TS, Harrold LR, et al.
Incidence and preventability of adverse drug events among older
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4. Moore C, Wisnivesky J, Williams S, McGinn T.
Medical errors related to discontinuity of care from an inpatient
to an outpatient setting. J Gen Intern Med. 2003;18:646-51.[ go to PubMed ]
5. Forster AJ, Murff HJ, Peterson JF, Gandhi TK,
Bates DW. The incidence and severity of adverse events affecting
patients after discharge from the hospital. Ann Intern Med.
2003;138:161-7.[ go to PubMed ]
6. Bonini P, Plebani M, Ceriotti F, Rubboli F.
Errors in laboratory medicine. Clin Chem. 2002; 48:5:691-8.[ go to PubMed ]
7. Khoury M, Burnett L, Mackay MA. Error rates in
Australian chemical pathology laboratories. Med J Aust.
1996;165:128-30.[ go to PubMed ]
8. Astion ML, Shojania KG, Hamill TR, Kim S, Ng
VL. Classifying laboratory incident reports to identify problems
that jeopardize patient safety. Am J Clin Pathol.
2003;120:18-26.[ go to PubMed ]
9. Nutting PA, Main DS, Fischer PM, et al. Toward
optimal laboratory use. Problems in laboratory testing in primary
care. JAMA. 1996;275:635-9.[ go to PubMed ]
10. Cullen DJ, Bates DW, Small SD, Cooper JB,
Nemeskal AR, Leape LL. The incident reporting system does not
detect adverse drug events: a problem for quality improvement. Jt
Comm J Qual Improv. 1995;21:541-548.[ go to PubMed ]
11. McDermott RE, Mikulak RJ, Beauregard MR. The
basics of FMEA. Portland, OR: Resource Engineering, Inc.; 1996.
12. Joint Commission on Accreditation of
Healthcare Organizations. 2003 National Patient Safety Goals.
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