Study examines use of age-adjusted D-dimer levels to exclude lung blood clots

March 18, 2014

Using a patient's age to raise the threshold for an abnormal result of a blood test used to assess patients with a suspected pulmonary embolism (blood clot in lungs) appeared to be safe and led to fewer healthy patients with the diagnosis, according to a study in the March 19 issue of JAMA.

D-dimer is a breakdown product of a blood clot, and measuring D-dimer levels is one way doctors exclude a diagnosis of (PE). Several studies have shown that D-dimer levels increase with . As a result, the proportion of healthy with abnormal test results (above 500 µg/L for most available commercial tests) increases with age, limiting the test's clinical usefulness in older people, according to background information in the article.

Marc Righini, M.D., of Geneva University Hospital, Geneva, Switzerland, and colleagues examined whether an age-adjusted D-dimer threshold, which involved redefining the test value that distinguished abnormal and normal results by multiplying the patient's age by 10 in patients 50 years or older, safely excluded the diagnosis of PE in elderly patients with suspected PE. The study, conducted at 19 centers in Belgium, France, the Netherlands, and Switzerland between January 2010 and February 2013, included outpatients who underwent a clinical probability assessment (measured by one of two scoring systems based on risk factors and clinical findings), D-dimer measurement, and computed tomography pulmonary angiography (CTPA; image of lungs).

Of the 3,346 patients with suspected PE included in the analysis, the prevalence of PE was 19 percent. The researchers found that combining the probability assessment with adjustment of the D-dimer cutoff for patient age safely excluded the diagnosis of PE and was associated with a low likelihood of subsequent PE or other venous blood clot. In , there was an increase in the proportion of patients in whom PE could be excluded without further imaging.

"Future studies should assess the utility of the age-adjusted cutoff in clinical practice. Whether the age-adjusted cutoff can result in improved cost-effectiveness or quality of care remains to be demonstrated," the authors conclude.

Explore further: Aspirin may prevent DVT and PE in joint replacement patients

More information: DOI: 10.1001/jama.2014.2135

Related Stories

Aspirin may prevent DVT and PE in joint replacement patients

February 7, 2012

Following a total joint replacement, anticoagulation (blood thinning) drugs can prevent Deep Vein Thrombosis (DVT), a blood clot deep within the extremities, or a pulmonary embolism (PE), a complication that causes a blood ...

Unsuspected PE does not up mortality risk in cancer patients

August 6, 2012

(HealthDay) -- Cancer patients with an unsuspected pulmonary embolism (UPE) do not have an increased mortality risk and have a similar risk of recurrent venous thromboembolism (VTE) to those with clinically suspected pulmonary ...

Unsuspected PE seldom linked to death in cancer patients

October 9, 2012

(HealthDay)—Unsuspected pulmonary embolism (UPE) is not associated with an increased risk of death in cancer patients when compared to patients without pulmonary embolism (PE), according to research published in the October ...

Recommended for you

Monkeys in Asia harbor virus from humans, other species

November 19, 2015

When it comes to spreading viruses, bats are thought to be among the worst. Now a new study of nearly 900 nonhuman primates in Bangladesh and Cambodia shows that macaques harbor more diverse astroviruses, which can cause ...

One-step test for hepatitis C virus infection developed

November 14, 2015

UC Irvine Health researchers have developed a cost-effective one-step test that screens, detects and confirms hepatitis C virus (HCV) infections. Dr. Ke-Qin Hu, director of hepatology services, will present findings at the ...

Computer model reveals deadly route of Ebola outbreak

November 10, 2015

Using a novel statistical model, a research team led by Columbia University's Mailman School of Public Health mapped the spread of the 2014-2015 Ebola outbreak in Sierra Leone, providing the most detailed picture to date ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.