Adapting the D-dimer cutoff for thrombosis detection in elderly outpatients

Abstract

D-dimer measurement is an important step in diagnostic strategies for venous thromboembolism. It allows the safe ruling out of the diagnosis with no need for imaging tests in approximately 30% of outpatients. However, the usefulness of d-dimer is limited in elderly patients; the likelihood of a negative d-dimer strongly decreases with age, making physicians reluctant to order the test. Several attempts to improve the performance of d-dimer in elderly patients have been pursued. Recently, an age-adjusted cutoff was derived; the optimal cutoff value (in µg/l) appears to be equal to the patient’s age (in years) multiplied by ten in patients over 50 years of age with a low pretest clinical risk of venous thromboembolism. This age-adjusted cutoff value has been extensively and externally validated in retrospective studies that included mostly outpatients with suspected deep vein thrombosis or pulmonary embolism and used various quantitative d-dimer assays. All available studies confirmed the increased usefulness and similar safety of the age-adjusted cutoff compared with the conventional cutoff, the most important benefit being obtained in elderly patients. However, before any recommendation for clinical practice can be made, a prospective diagnostic management outcome study is lacking, in which all low clinical risk patients with d-dimer levels below their age-adjusted cutoff would be left untreated with no further diagnostic testing.

Keywords::

• aged
• age factors
• biological markers
• blood
• d-dimer
• deep vein thrombosis
• diagnosis
• diagnostic tests
• predictive tests
• pulmonary embolism
• sensitivity
• specificity
• venous thromboembolism

Financial & competing interests disclosure

G Gal and M Righini received honoraria and research funding from bioMerieux. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.