Causes of elevated D-dimer in patients admitted to a large urban emergency department.
BACKGROUND
Although the request for D-dimer is widespread in emergency departments (EDs), the causes of elevation and their relationship with D-dimer levels in patients with diagnostic values are uncertain.


METHODS
In this retrospective investigation, the study population consisted of all patients who visited our large urban ED in the year 2012, for whom a D-dimer test was requested for excluding or diagnosing venous thromboembolism (VTE). Only patients with D-dimer values >243ng/mL were included, regardless of their pre-test clinical probability for VTE.


RESULTS
The final study population consisted of 1647 patients. A significant positive correlation was found between age and D-dimer. Infection was the most frequent diagnosis (15.6%), followed by VTE (12.1%), syncope (9.4%), heart failure (8.9%), trauma (8.2%) and cancer (5.8%). D-dimer was higher in patients with VTE than in those with other diagnoses (2541ng/mL vs 1030ng/mL; p<0.001). The frequency of VTE gradually increased from patients with values <1000ng/mL to those with D-dimer >3000ng/mL (4.1 vs 26.7%; p<0.001). As compared with D-dimer values <1000ng/mL, the Odds Ratio for VTE was 8.5 for values >3000ng/mL.


CONCLUSIONS
These results show that D-dimer lacks specificity for diagnosing VTE, especially in elderly patients admitted to the ED with significant co-morbidities. In older patients, elevated values (>1000ng/mL) are more frequently associated with VTE, so the use of higher cut-offs may be advantageous.
Laboratory of Clinical Chemistry and Hematology, Academic Hospital of Parma, Parma, Italy. Electronic address: glippi@ao.pr.it.
Giuseppe
G
Lippi
Emergency Department, Academic Hospital of Parma, Parma, Italy.
Laura
L
Bonfanti
Emergency Department, Academic Hospital of Parma, Parma, Italy.
Carlotta
C
Saccenti
Emergency Department, Academic Hospital of Parma, Parma, Italy.
Gianfranco
G
Cervellin
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001424:Bacterial Infections / Q000097:blood; D015331:Cohort Studies; D004636:Emergency Service, Hospital; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006333:Heart Failure / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood; D016017:Odds Ratio; D011014:Pneumonia / Q000097:blood; D011655:Pulmonary Embolism / Q000097:blood* / Q000175:diagnosis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013575:Syncope / Q000097:blood; D014505:Urban Population; D054556:Venous Thromboembolism / Q000097:blood* / Q000175:diagnosis; D020246:Venous Thrombosis / Q000097:blood* / Q000175:diagnosis; D014947:Wounds and Injuries / Q000097:blood
D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D
D-dimer testing; Emergency department; Thrombosis; Venous thromboembolism