EVALUATION OF D-DIMER ELISA TEST IN ELDERLY PATIENTS WITH SUSPECTED PULMONARY-EMBOLISM

Study Objective: To determine the clinical usefulness of D-dimer ELISA test in elderly patients with clinically suspected pulmonary embolism (PE). Design: Prospective cohort study. Patients: Ninety-six consecut ive outpatients older than 70 years with a duration of symptoms shorte r than one week and without metastatic cancer or recent surgery, traum a, infection, stroke, myocardial infarction, deep vein thrombosis (DVT ) or PE, or treatment with curative doses of heparin or oral anticoagu lant. Intervention: All patients underwent at least ventilation/perfus ion scan and bilateral ultrasonic duplex scan and a blood sample colle ction within 24 hours of admission. When necessary a pulmonary angiogr aphy and/or a bilateral venography were also performed. Patients were classified as follows: (1) PE-positive; positive angiography or high p robability V/Q scan and deep vein thrombosis (proven either by venogra phy or by ultrasonic duplex scan) or non high probability V/Q scan and either DVT (proven at presentation by venography or by ultrasonic dup lex scan) or symptomatic thromboembolic event within 3 months of follo w-up; or (2) PE-negative; normal V/Q scan or normal angiography or non high probability V/Q scan and either negative ultrasonic duplex scan or normal venography and low clinical probability and absence of sympt omatic thromboembolism within 3 months of follow-up. D-dimer measureme nts were performed using both a conventional and a single semi-quantit ative ELISA test (Asserachrom D-di, Instant I.A.D-dimer). Results: Usi ng a cutoff value of 500 ng/ml, the conventional ELISA D-dimer test sh owed a sensitivity and a negative predictive value of 100% with poor s pecificity and positive predictive value of 14.3% and 45.5% respective ly. The new rapid semi-quantitative D-dimer test displays worse result s with sensitivity, negative predictive value, specificity and positiv e predictive value of 92.3%, 82.4%, 25% and 46% respectively. Conclusi on: In a geriatric population, conventional ELISA D-dimer is a good ma rker to exclude PE but. due to the comorbid conditions, only a few pat ients presented with D-dimer values less than 500 ng/ml.