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Understanding MOC Requirements
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April 11-13, 2019
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Overuse of computed tomography and D-dimer testing may not
improve care and lead to patient harm and unnecessary
Philadelphia, September 29, 2015 -- When evaluating patients
with suspected acute pulmonary embolism (PE), physicians should
stratify patients into groups for whom different diagnostic
strategies are appropriate, the American College of Physicians
(ACP) advises in a new paper
published today in Annals of Internal Medicine.
"The use of computed tomography (CT) for the evaluation of
patients with suspected pulmonary embolism is increasing despite no
evidence that this increased use has led to improved patient
outcomes, while exposing patients to unnecessary risks and
expense," said ACP President Dr. Wayne J. Riley. "ACP's advice is
designed to help physicians identify patients for whom a PE is so
unlikely that they need no further testing, for whom plasma D-dimer
testing can provide additional risk stratification, and for whom
imaging is indicated because of their high risk and clinical
A serum d-dimer test is a blood test to check for the presence
of blood clots.
The first step for physicians when evaluating patients with
suspected acute PE is to use a validated clinical prediction rule
to estimate their pre-test probability of PE. The benefit of such a
decision tool is that it helps standardize the evaluation for
physicians who infrequently encounter and/or evaluate patients for
PE, ACP advises. The Wells and Geneva rules have been validated and
are considered equally accurate in predicting the probability of
In patients who have a low pre-test probability of PE,
physicians should apply the PERC (Pulmonary Embolism Rule-Out
Criteria) rule. Physicians should not obtain D-dimer tests or
imaging studies in patients with a low pre-test probability of PE
and who meet all eight PERC.
Patients who have an intermediate pre-test probability of PE or
patients with low pre-test probability of PE who do not meet all
PERC should have a high sensitivity D-dimer test as the initial
step in diagnosis. Physicians should not use imaging studies as the
initial test in patients who have a low or intermediate pre-test
probability of PE.
Since normal D-dimer levels increase with age, physicians should
use age-adjusted D-dimer thresholds (age times 10 ng/mL rather than
a generic 500 ng/mL) in patients older than 50 years to determine
whether imaging is warranted. Physicians should not obtain any
imaging studies in low or intermediate risk patients with a D-dimer
below the age-adjusted cutoff.
"While highly sensitive, plasma D-dimer testing is nonspecific
and false-positives can lead to unnecessary imaging," said Dr. Ali
S. Raja, Vice Chair, Department of Emergency Medicine,
Massachusetts General Hospital, who co-authored the paper for ACP's
Clinical Guidelines Committee. "The use of an age-adjusted
threshold resulted in maintenance of sensitivities with improved
specificities in all age groups."
Patients with high pre-test probability of PE should obtain
imaging with CT pulmonary angiography. Physicians should reserve
V/Q scans for patients who have a contraindication for CT pulmonary
angiography or if CT pulmonary angiography is not available.
Physicians should avoid obtaining a D-dimer measurement in patients
with a high pre-test probability of PE.
ACP offers a Patient
FACTS piece, a patient-tested resource designed to help
patients and their caregivers increase their understanding of
pulmonary embolism. A summary for patients was also published in
Annals of Internal Medicine.
A pulmonary embolism is a sudden blockage in a lung artery. The
cause is usually a blood clot in the leg called a deep vein
thrombosis that breaks loose and travels through the bloodstream to
About the American College of Physicians
The American College of Physicians is the largest
medical specialty organization and the second-largest physician
group in the United States. ACP members include 143,000 internal
medicine physicians (internists), related subspecialists, and
medical students. Internal medicine physicians are specialists who
apply scientific knowledge and clinical expertise to the diagnosis,
treatment, and compassionate care of adults across the spectrum
from health to complex illness. Follow ACP on Twitter and Facebook.