INTRODUCTION
We are reporting the results of a survey of the U.S.
hospital coagulation laboratory practices conducted in 2001. The Centers for
Disease Control and Prevention (CDC) contracted with Research Triangle
Institute (RTI), Durham, NC to conduct this survey. RTI subcontracted
with Analytical Sciences, Inc. (ASI), Durham, NC to assist the CDC in the
development and administration of this survey to a sample of the U.S.
hospital laboratories.
Hospital clinical laboratories play an important role in the
health of Americans; and as documented in this survey, virtually all
hospital laboratories performed some coagulation tests. Coagulation
laboratory testing is vital to the diagnosis, treatment and management of
bleeding and hypercoagulability disorders affecting millions of patients in
the U.S. For example, the most commonly performed coagulation test,
prothrombin time (PT) assay, is currently performed over 40 million times
annually. The majority of coagulation laboratory tests are performed as
screening tests for coagulation disorders or to monitor therapeutic
anticoagulant therapy; these assays are also used in conjunction with other
tests to increase overall diagnostic accuracy. Although variation in
coagulation testing practices within individual laboratories has been
documented, little is known about the extent or nature of variation across
hospital laboratories. Variability in some testing processes can affect test
result accuracy and result interpretation, potentially impacting patient
outcomes (e.g., complications of bleeding or thrombosis). Given that the
diagnosis and treatment of many patients depend, in part, on coagulation
testing, such variation could have serious consequences for patient and
population health care and assessment.
In response to the uncertainty surrounding coagulation
testing practices, we conducted this national survey of hospital coagulation
laboratories. This survey focused on testing practices involving 3
coagulation disorders potentially impacting patient outcomes. These
disorders were (1) hypercoagulability or thrombophilia, (2) von Willebrand
disease (vWD), and (3) heparin induced thrombocytopenia
(HIT)/heparin-induced thrombocytopenia thrombotic syndrome (HITTS). We chose
these disorders because, in our judgment along with that of a panel of
coagulation laboratory experts,* (1) they had serious health
consequences affecting a large number of people and (2) valid test results
were critical for their diagnosis and treatment.
Our purpose here was to assess variation of coagulation
laboratory practices in the U.S. hospitals by assessing
- availability of specific tests for diagnosing and treating
hypercoagulability or thrombophilia, vWD and HIT/HITTS,
- pre-analytical issues such as collection methods, information provided
with specimens, and processing of specimens,
- analytical issues such as instrumentation, quality control (QC), and
qualifications of testing personnel,
- post-analytical issues such as result reporting, interpretations, and
recommendations, and
- use of selected laboratory practices specific to each test that are
subject to variation (such as availability, methodology and sensitivity)
and that are critical to the diagnostic or therapeutic use of the test.
*The members of this panel were Michael Laposata,
M.D., Ph.D. of Harvard Medical School, Boston, MA, Connie Miller, Ph.D. of
the CDC, Atlanta, GA, Stephan Moll, M.D. of the University of North
Carolina, Chapel Hill, NC, and John Olson, M.D., Ph.D. of the University of
Texas Health Science Center, San Antonio, TX.
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