D-dimer values to rule out pulmonary emboli in older patients

January 01, 0001

D-dimer values to rule out pulmonary emboli in older patients

The d-dimer is a lab test, that when negative, can be helpful in ruling out a pulmonary emboli. These European researchers sought to establish a new D-dimer cut-off point in patients aged over 50 years using data from two multicentre cohort studies. This new cut-off value was then validated using two independent validation datasets.

The researchers report: "The new D-dimer cut-off value was defined as (patient’s agex10) µg/l in patients aged over 50. In 1331 patients in the derivation set with an "unlikely" score from clinical probability assessment, pulmonary embolism could be excluded in 42% with the new cut-off value versus 36% with the old cut-off value (less than 500 µg/l). In the two validation sets, the increase in the proportion of patients with a D-dimer below the new cut-off value compared with the old value was 5% and 6%. This absolute increase was largest among patients aged over 70 years, ranging from 13% to 16% in the three datasets. The failure rates (all ages) were 0.2% in the derivation set and 0.6% and 0.3% in the two validation sets."

The authors concluded: "The age adjusted D-dimer cut-off point, combined with clinical probability, greatly increased the proportion of older patients in whom pulmonary embolism could be safely excluded."

This study finds higher d-dimer cut-off may be used more effectively to rule out pulmonary emboli in older patients.

For the full abstract, click here.

BMJ 340: c1475, 30 March 2010
© 2010 Douma et al.
Potential of an age adjusted D-dimer cut-off value to improve the exclusion of pulmonary embolism in older patients: a retrospective analysis of three large cohorts. Renée A Douma, Gregoire le Gal, Maaike Sohne, et al. Correspondence to R A Douma: [email protected]

Category: R. Respiratory. Keywords: d-dimer, pulmonary embolus, clinical probability, geriatric, elderly, cut-off, diagnostic test evaluation study, journal watch.
Synopsis edited by Dr Paul Schaefer, Toledo, Ohio. Posted on Global Family Doctor 20 April 2010

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