age guidelines for d dimer
For each individual subject, a VTE recurrence score was calculated based on a sum of scores of four predictors: age, sex, hormone use at the time of the VTE, and D-dimer measured three weeks after stopping oral anticoagulation. The final prognostic score was based on regression coefficients for each predictor (Table). A score of +2 was assigned for abnormal D-dimer, +1 for age &lt; 50 years old, +1 for male sex, and -2 for hormone use at onset of VTE (among women), generating a D2A1S1H-2 score. Among these, 539 were negative for D-dimers and 465 were positive. Mean age was 74 years (19–99 years) for patients positive for D-dimers, and 48 years (18–93 years) for patients negative for D-dimers ( ). Only 12% of patients aged 70 or above had negative D-dimers. In the group of patients positive for D-dimers, 67 (14%) had a diagnosis of either DVT ( , 3%) or PE ( , 11%). 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. Diagnostic accuracy of conventional or age adjusted D-dimer cut-off values in older patients with suspected venous thromboembolism: systematic review and meta-analysis>. BMJ. 2013 May 3;346:f2492. Abstract. The age-adjusted D-dimer threshold was more specific (64% versus 54%) but less sensitive (93% versus 98%) than the standard threshold of 500 ng/dL; 11,999 imaging studies identified 507 pulmonary embolisms (4.2%); of these, 1,323 (10.6%) were performed with a D-dimer result below the standard threshold. Reference Range. D-dimer is the degradation product of crosslinked (by factor XIII) fibrin. It reflects ongoing activation of the hemostatic system. The reference concentration of D-dimer is less than 0.5 µg/mL fibrinogen-equivalent units (FEU) Quantitative D-dimer assay result can be reported as either concentration of D-dimer or as FEUs, depending on the calibration method. A D-dimer level higher than 500 µg/L but below the age-adjusted cutoff ruled out the diagnosis of PE, with a 3-month risk of venous thromboembolism in line with that observed in patients with a D-dimer level lower than 500 µg/L or after a negative pulmonary angiography result, the gold-standard test for PE. Another 157 patients (23.3%) had a D-dimer level lower than their age-adjusted cutoff. Therefore, the proportion of patients older than 75 years with a nonhigh or unlikely clinical probability and a negative D-dimer result using the age-adjusted cutoff was 200 of 673 patients (29.7% [95% CI, 26.4%-33.3%]). Among the 2898 patients with a nonhigh or an unlikely clinical probability, 817 patients (28.2%) had a D-dimer level lower than 500 µg/L (95% CI, 26.6%-29.9%) and 337 patients (11.6%) had a D-dimer between 500 µg/L and their age-adjusted cutoff (95% CI, 10.5%-12.9%). We determine the accuracy of an age-adjusted D-dimer threshold to detect pulmonary embolism in emergency department (ED) patients older than 50 years and describe current ED practices when evaluating possible pulmonary embolism. This was a retrospective study of ED encounters for suspected pulmonary embolism from 2008 to 2013.
A score of +2 was assigned for abnormal D-dimer +1 for age & lt 50 years old, +1 for male sex and -2 for hormone use at onset of VTE  generating a D2A1S1H-2 score.