Different D-dimer assays with age-adjusted cutoffs to exclude pulmonary embolism: secondary analysis of ADJUST-PE study

BACKGROUND: The multicenter prospective ADJUST-PE study proved the safety of an age-adjusted D-dimer (AADD) cutoff to exclude pulmonary embolism (PE). OBJECTIVES: Assess the safety of different D-dimer (DD) assays using AADD in patients included in ADJUST-PE in Geneva compared with the originally used VIDAS DD Exclusion test. METHODS: This was a preplanned secondary analysis. The VIDAS DD Exclusion test was repeated to ensure reproducible results in thawed samples. Other tests performed were Innovance DD test, STA Liatest, Tina-quant DD, and the point-of-care LumiraDx test. The main outcome was venous thromboembolic risk (VTE) at initial testing or within 3 months after PE exclusion by a negative DD test using AADD ("failure rate"). The secondary outcome measure was to compare each assay with VIDAS in the classification of patients as having a negative vs positive AADD result. RESULTS: A total of 602 patients were included and 597 were available for analysis. Fourteen percent had PE confirmed at baseline. Failure rates were <2% for all tests. The risk of a change in classification from positive original VIDAS AADD to negative AADD result was similar to the repeated VIDAS (comparator) for Innovance and LumiraDx and higher for STA Liatest and Tina-quant. For the latter 2 assays, 3 and 5 patients with negative AADD had PE, respectively. CONCLUSION: Innovance and LumiraDx assays had similar safety in excluding PE by AADD compared with VIDAS. STA Liatest and Tina-quant classified a higher proportion of patients with a negative AADD, among whom 3 and 5 had PE, respectively.