Objectives In older patients, the the D-dimer test for pulmonary embolism has reduced specificity and is therefore less useful. In this study a new, age dependent cut-off value for the test was devised and its usefulness with older patients assessed. Design Retrospective multicentre cohort study. Setting General and teaching hospitals in Belgium, France, the Netherlands, and Switzerland. Patients 5132 consecutive patients with clinically suspected pulmonary embolism. Intervention Development of a new D-dimer cut-off point in patients aged >50 years in a derivation set (data from two multicentre cohort studies), based on receiver operating characteristics (ROC) curves. This cut-off value was then validated with two independent validation datasets. Main outcome measures The proportion of patients in the validation cohorts with a negative D-dimer test, the proportion in whom pulmonary embolism could be excluded, and the false negative rates. Results The new D-dimer cut-off value was defined as (patient's age×10) μg/l in patients aged >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 (<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 > 70 years, ranging from 13% to 16% in the three datasets. The failure rates (all ages) were 0.2% (95% CI 0% to 1.0%) in the derivation set and 0.6% (0.3% to 1.3%) and 0.3% (0.1% to 1.1%) in the two validation sets. Conclusions 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.

clinicaltrials.gov Identifier: NCT01134068.

Objective To review the diagnostic accuracy of D-dimer testing in older patients (>50 years) with suspected venous thromboembolism, using conventional or age adjusted D-dimer cut-off values.Design Systematic review and bivariate random effects meta-analysis. Data sourcesWe searched Medline and Embase for studies published before 21 June 2012 and we contacted the authors of primary studies.Study selection Primary studies that enrolled older patients with suspected venous thromboembolism in whom D-dimer testing, using both conventional (500 µg/L) and age adjusted (age×10 µg/L) cut-off values, and reference testing were performed. For patients with a non-high clinical probability, 2×2 tables were reconstructed and stratified by age category and applied D-dimer cut-off level.Results 13 cohorts including 12 497 patients with a non-high clinical probability were included in the meta-analysis. The specificity of the conventional cut-off value decreased with increasing age, from 57.6% (95% confidence interval 51.4% to 63.6%) in patients aged 51-60 years to 39.4% (33.5% to 45.6%) in those aged 61-70, 24.5% (20.0% to 29.7% in those aged 71-80, and 14.7% (11.3% to 18.6%) in those aged >80. Age adjusted cut-off values revealed higher specificities over all age categories: 62.3% (56.2% to 68.0%), 49.5% (43.2% to 55.8%), 44.2% (38.0% to 50.5%), and 35.2% (29.4% to 41.5%), respectively. Sensitivities of the age adjusted cut-off remained above 97% in all age categories. ConclusionsThe application of age adjusted cut-off values for D-dimer tests substantially increases specificity without modifying sensitivity, thereby improving the clinical utility of D-dimer testing in patients aged 50 or more with a non-high clinical probability. IntroductionD-dimer concentrations are highly sensitive for thrombus formation. Hence D-dimer tests are often used to rule-out venous thromboembolism (pulmonary embolism or deep vein thrombosis) in suspected patients with a non-high clinical probability. Patients with a high clinical probability do not require a D-dimer test. In these patients imaging examination is warranted to confirm or refute the diagnosis, irrespective of the D-dimer results ( fig 1⇓).1-3 However, D-dimer concentrations increase with age, which leads to a high proportion of older patients with D-dimer concentrations higher than conventional cut-off values (500 µg/L).4 5 This in turn leads to a low specificity (that is, more false positive results) of D-dimer testing in older patients suspected of having venous thromboembolism; the specificity is 49% to 67% for patients aged less than 50 years but in older old patients (≥80 years) between 0% and 18%.4-8 As imaging is indicated in patients suspected of having venous thromboembolism with a D-dimer concentration above the cut-off value, 9 a high proportion of older patients with a non-high clinical probability undergo unnecessary diagnosticCorrespondence to: H J Schouten h.j.schouten-3@umcutrecht.nl Extra material supplied by the author (see

In patients with acute PE, MDCT might be used as a single procedure for diagnosis and risk stratification. Patients without right ventricular dysfunction at MDCT have a low risk of in-hospital adverse outcome.

Academic Medical Center, VU University Medical Center, Rijnstate Hospital, Leiden University Medical Center, Maastricht University Medical Center, Erasmus Medical Center, and Maasstad Hospital.