Age-adjusted cut-off using the IL D-dimer HS assay to exclude pulmonary embolism in patients presenting to emergency.
BACKGROUND/AIM
The ADJUST-PE study showed that an age-adjusted D-dimer (AADD) (age years × 10 ng/mL if >50 years) combined with an unlikely pre-test probability (PTP) can increase the proportion of older patients in whom pulmonary embolism (PE) can be safely excluded, but the IL D-dimer HS assay was not assessed. To assess the ability of the IL D-dimer HS assay to exclude PE using the AADD.


METHODS
Retrospective analysis of consecutive patients presenting with symptoms of acute PE to one of three Monash Health Emergency Departments (January 2013-January 2014) who had computed tomography pulmonary angiography. In the group with D-dimer, efficiency (proportion of PE excluded based on a combination of unlikely PTP and negative D-dimer) was determined using (i) current laboratory (200 ng/mL), (ii) conventional (230 ng/mL) and (iii) modified (375 ng/mL if age ≥60 years) AADD cut-offs.


RESULTS
A total of 176 patients with D-dimers was included (mean age = 58.5 years; 54.0% males; 71.0% age >50 years). Prevalence of PE in the overall, unlikely and likely PTP groups, was 17.0, 13.0 and 24.6% respectively. In the unlikely PTP group (115 patients), efficiency for the current, conventional, modified and AADD cut-offs was 9.6, 24.3, 30.4 and 37.4% respectively.


CONCLUSION
The absolute increase in efficiency of an AADD compared to conventional cut-off using the IL D-dimer HS assay is modest (~10%) and requires prospective validation. Modifying our cut-off to 230 ng/mL and systematic implementation of a clinical algorithm, including D-dimer testing and PTP, is likely a more important first step.
['Lim|Ming S|MS|0000-0003-4616-330X', 'Bennett|Ashwini|A|', 'Chunilal|Sanjeev|S|']
D000328:Adult D000367:Age Factors D000368:Aged D000465:Algorithms D001315:Australia D000072226:Computed Tomography Angiography D003937:Diagnosis, Differential D004636:Emergency Service, Hospital D005260:Female D005338:Fibrin Fibrinogen Degradation Products D006801:Humans D008297:Male D008875:Middle Aged D011237:Predictive Value of Tests D011336:Probability D011655:Pulmonary Embolism D012372:ROC Curve D012189:Retrospective Studies
D-dimer pulmonary embolism pre-test probability age adjusted computed tomography pulmonary angiogram