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Age-adjusted D-dimer cut-off in the diagnostic strategy for deep vein thrombosis: a systematic review
1a Department of Clinical Biochemistry and Pharmacology , Odense University Hospital , Odense , Denmark.
Background:
Studies have indicated that use of an age-adjusted D-dimer cut-off value for patients above 50 years increases utility of the diagnostic strategy for pulmonary embolism. Evidence for the same approach regarding diagnosis of deep vein thrombosis (DVT) is, however, unclear.
Materials And Methods:
A systematic literature review was conducted following the PRISMA Statement guideline to gather the existing knowledge on the use of an age-adjusted D-dimer cut-off in the diagnostic strategy for DVT. Studies were extracted from Medline and the Cochrane Library. The search period ended in November 2016.
Results:
Out of 73 articles retrieved, only eight studies addressed DVT either specifically or along with PE. None of these were randomized controlled trials, but were either prospective studies of consecutive outpatients or retrospective studies. Despite differences in study design, DVT prevalence, and D-dimer assay used, all studies were in favour of the age-adjusted D-dimer cut-off with negative predictive values (NPV) ranging from 91.8-100% compared to 89.7-100% for the standard D-dimer cut-off. All the studies concluded that use of an age-adjusted D-dimer cut-off resulted in an improved utility, although the results due to heterogeneity in reporting did not allow a direct comparison.
Conclusion:
Use of an age-adjusted D-dimer cut-off for patients above 50 years of age for ruling out DVT seems as safe as using a standard D-dimer cut-off. The recommended (and most used) adjustment is by the formula (patient's age ×10) μg/L.