The impact of symptom duration on D-dimer: results from the Venous Thrombosis Registry in Østfold Hospital.

Background: It has been suggested that D-dimer testing should be avoided in patients with prolonged symptoms, as results may yield false negatives. However, the evidence supporting this recommendation is limited. Objectives: This study evaluated the impact of symptom duration on D-dimer and investigated associations between false-negative D-dimer results and prolonged symptoms. Methods: Patients diagnosed with pulmonary embolism, deep vein thrombosis (DVT), or upper extremity DVT between 2005 and 2020 were identified through the Venous Thrombosis Registry in Results: In total 3423 patients were included, of whom 1696 (49.5%) were women, with a median age of 67 years (IQR, 54-78 years). The median symptom duration was 4 days (IQR, 2-10 days), and 946 patients (27.6%) reported symptoms exceeding 1 week. D-dimer showed a weak negative correlation with symptom duration (Kendall τ coefficient = -0.04; Conclusion: Although D-dimer were negatively correlated with symptom duration, the coefficient was very weak and unlikely to have clinical relevance. Moreover, false-negative D-dimer results were not associated with prolonged symptoms, suggesting that extended symptom duration may not affect the performance of D-dimer testing in clinical practice.