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Prothrombin Time Testing Practices in the Pacific Northwest:
A Model for Monitoring Voluntary Practice Guidelines
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Survey Home
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Background
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Medical mistakes and errors are unacceptably high, despite a longstanding focus
on activities carried out in the name of total quality management, quality
assurance (QA), and quality assessment. In 1999, a report by the Institute of
Medicine (IOM) revealed the magnitude of medical errors and concluded that most
were the result of systematic failures and were preventable (1). Therefore, the
right changes in systems should result in the reduction of errors. Approaches
to reducing medical errors include
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tracking errors and determining their causes,
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monitoring indicators of quality, and
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overcoming barriers to adhere to accepted standards of laboratory practice.
In clinical laboratory medicine, practice standards and guidelines are not new.
Federal regulatory standards addressing laboratory QA programs have been in
existence for hospitals and independent laboratories since 1967 [Clinical
Laboratory Improvement Act of 1967 (CLIA '67)] and for all other testing
facilities since 1992 [Clinical Laboratory Improvement Amendments of 1988 (CLIA
'88)]. While government standards set the tone for laboratory testing quality,
they represent minimal requirements and allow individual testing sites much
latitude in their implementation.
More rigorous voluntary practice standards exist for laboratories that wish to
be accredited by a private accrediting organization, in lieu of being
directly certified by the Government. While the College of American
Pathologists (CAP), the Joint Commission on Accreditation of Healthcare
Organizations (JCAHO), the American Association of Blood Banks (AABB), COLA and
other accrediting organizations offer excellent standards of practice, the
majority of laboratories are not accredited.
Studies have shown that despite required and voluntary standards of practice,
many laboratorians fail to use them (2). Although quality laboratory work may
be their aim, many personnel lack the resources to adhere to the "state of the
art" voluntary protocols or recommendations. In addition, many facilities use
only CLIA-waived test systems, which are not subject to regulation other than
the requirement to follow current manufacturer's instructions.
One common laboratory test that is vulnerable to errors and adverse patient
outcomes is the prothrombin time (PT) test. Nearly all hospitals perform the PT
test, but it is also performed in many non-hospital settings as well.
Systematic changes in test results that are not due to biological reasons can
occur when patients move from one setting to another due to a lack of
correlation between methods and a lack of communication between sites. A
patient may be tested while an inpatient in the hospital (by the traditional
laboratory and/or at the nursing station). They may then visit an
anticoagulation center as an outpatient or be tested in their physician's
office. In some cases, patients may perform PT testing at home, using one of
the prescription home use devices now available. How does the patient's
physician make sense of the PT values when test results come from all these
different settings, with different reference ranges, reporting formats, reagent
systems, etc?
Errors may also occur when a testing site changes to a new lot of testing
reagents. Testing personnel may not recognize that their reagent sensitivity
has changed and may not do studies to verify their test results are consistent
and calculations are accurate.
Prothrombin time testing is now commonly done by non-traditional test methods
[point-of-care (POC) and CLIA-waived test devices]. These devices differ from
traditional laboratory methodologies by using capillary whole blood samples,
unitized reagent strips or cartridges, electronic quality control (QC), pre-set
values for the international sensitivity index (ISI), "mean of normal,"
reference ("normal") ranges, and the automatic calculation of the international
normalized ratio (INR). Prothrombin time testing using these devices is common
in non-traditional settings (POC and waived test sites) where there is the
advantage of the patients being present along with their medical records at the
time of testing. However, these sites often have minimal requirements for QC,
QA, and testing personnel qualifications. Many current practice standards and
guidelines for PT testing were not written with these non-traditional test
methods or settings in mind.
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Purpose of the project
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In October 2003, the Washington State Office of Laboratory Quality Assurance
(LQA) and the Centers for Disease Control and Prevention (CDC) entered into a
cooperative agreement to study laboratory testing practices in the Pacific
Northwest. Using PT testing as a model, the purpose of this project was to
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evaluate current laboratory testing practices,
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determine which practice standards and guidelines laboratories use,
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assess the reasons testing sites do not adhere to accepted standards of
practice,
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compare practices in different settings and by different test methods, and
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educate laboratory personnel about the commonly accepted standards of practice.
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Method
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To gather information about current laboratory testing practices, a
questionnaire was developed in October-December 2003 by the LQA and CDC, and
was pilot-tested in 5 laboratories in Washington State in December 2003.
Using the Washington Medical Test Site (MTS) database and licensure application
forms, testing sites performing PT by either CLIA-waived or non-waived methods
were identified and targeted to receive the questionnaire. Laboratories located
in Alaska, Idaho and Oregon performing proficiency testing for PT were
identified using the CLIA (OSCAR) database. Questionnaires were mailed to the
591 such laboratories in the Pacific Northwest region on January 27, 2004. Two
hundred ninety-seven completed questionnaires were returned by March 19, 2004,
resulting in an overall response rate of 50.3% (Tables 1 and 2).
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Table 1 - Questionnaire respondents
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Site Type |
Laboratory Classification |
Location |
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Total
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Point of Care 1 |
Hospital |
IL2 |
Waived/ PPMP3 |
Moderate/ High4 |
Accredited |
Urban |
Rural |
| Alaska |
| Targeted |
42 |
18 |
21 |
3 |
2 |
14 |
26 |
7 |
35 |
| Respondent |
17 |
7 |
9 |
1 |
0 |
7 |
10 |
4 |
13 |
| Response Rate(%) |
40 |
39 |
43 |
33 |
0 |
50 |
38 |
57 |
37 |
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| Idaho |
| Targeted |
91 |
43 |
40 |
8 |
8 |
61 |
22 |
20 |
71 |
| Respondent |
46 |
15 |
27 |
4 |
3 |
33 |
10 |
7 |
39 |
| Response Rate(%) |
51 |
35 |
68 |
50 |
38 |
54 |
45 |
35 |
55 |
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| Oregon |
| Targeted |
187 |
103 |
59 |
25 |
25 |
61 |
101 |
110 |
77 |
| Respondent |
81 |
44 |
28 |
9 |
9 |
27 |
45 |
48 |
33 |
| Response Rate(%) |
43 |
43 |
47 |
36 |
36 |
44 |
45 |
44 |
43 |
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| Washington |
| Targeted |
271 |
169 |
78 |
24 |
84 |
111 |
76 |
187 |
84 |
| Respondent |
153 |
86 |
53 |
14 |
33 |
73 |
47 |
100 |
53 |
| Response Rate(%) |
56 |
51 |
68 |
58 |
39 |
66 |
62 |
53 |
63 |
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| Total |
| Targeted |
591 |
333 |
198 |
60 |
119 |
247 |
225 |
324 |
267 |
| Respondent |
297 |
152 |
117 |
28 |
45 |
140 |
112 |
159 |
138 |
| Response Rate(%) |
50 |
46 |
59 |
47 |
38 |
57 |
50 |
49 |
52 |
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1Point of care includes the following types of sites: POLs,
clinics, community health clinics, home health agencies, health maintenance
organizations (HMOs), and ambulatory surgical centers.
2IL = independent laboratory
3PPMP = provider performed microscopy procedure
4Moderate/High = moderate or high test complexity, but not accredited
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Table 2 - Comparison of respondent demographics
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Respondents
N = 2971 |
All labs targeted
N = 5911 |
All Pacific NW labs N = 6072 |
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Percent of laboratories |
| Alaska |
6 |
7 |
7 (N = 436) |
| Idaho |
15 |
15 |
12 (N = 724) |
| Oregon |
27 |
32 |
34 (N = 2069) |
| Washington |
52 |
46 |
47 (N = 2843) |
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| Urban/Rural |
54/46 |
55/45 |
67/33 |
| Point of care site2/Hospital/IL3 |
51/39/9 |
56/34/10 |
92/5/3 |
Waived & PPMP/
Moderate/High4 & Accredited |
15/85 |
20/80 |
75/25 |
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1Numerator data are not included since they can be obtained from Table 1.
2Point of care site includes the following types: POLs, clinics, community health clinics, home health agencies, health maintenance organizations (HMOs), and ambulatory surgical centers.
3IL = independent laboratory
4PPMP = provider performed microscopy procedure; Moderate/High = moderate or high test complexity, but not accredited
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In an instruction sheet that was provided with the questionnaires, we clarified the phrase
"voluntary practice standard" as documents published by professional organizations [such as the CLSI,
World Health Organization (WHO), CAP and others] whose use is voluntary, as opposed to regulatory or accreditation
requirements that must be followed for certification or accreditation.
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This page last reviewed: 3/7/2005
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