(HealthDay News) — Age-adjusted levels of D-dimer safely exclude pulmonary embolism (PE) in older patients, according to a study published in the March 19 issue of the Journal of the American Medical Association.

Marc Righini, MD, from Geneva University Hospital, and colleagues evaluated all consecutive outpatients presenting with clinically suspected PE. The sequential diagnostic strategy used a clinical assessment; highly sensitive D-dimer measurement; and computed tomography pulmonary angiography (CTPA) only when the D-dimer value was not between the conventional cutoff of 500µg/L and their age-adjusted cutoff.

The researchers found that, of the 2,898 patients with an unlikely clinical probability, 28.2% (817 patients) had a D-dimer level <500µg/L and 11.6% (337 patients) had a D-dimer between 500µg/L and their age-adjusted cutoff. The number of patients ≥75 years who had a non-high clinical probability (673 patients), in whom PE could be excluded on the basis of D-dimer, increased from 43 to 200 using the age-adjusted cutoff, without any additional false-negative findings.

“Compared with a fixed D-dimer cutoff of 500µg/L, the combination of pretest clinical probability assessment with age-adjusted D-dimer cutoff was associated with a larger number of patients in whom PE could be considered ruled out with a low likelihood of subsequent clinical venous thromboembolism,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.

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